Show the homemade equipment you are using now. - Page 1
Forum section: electronics / testgear

author: 001
author_rank: Super Contributor
timestamp: November 22, 2018, 04:24:13 am
content: Hi!Do You use homebrewered (DIY, selfmade) gear now? Show it!

author: capt bullshot
author_rank: Super Contributor
timestamp: November 22, 2018, 07:57:31 am
content: This is an 4 channel amplifier I made for special testing purposesHere's an debug adapter for very special purposes:http://wunderkis.de/vsl-dual/index.htmlAnd a somewhat larger 3 channel amplifier I made for no particular purpose:http://wunderkis.de/pwramp3/index.htmlMy first lab power supply:

author: guido
author_rank: Regular Contributor
timestamp: November 22, 2018, 10:07:50 pm
content: Ok, I'll biteMy isolation transformer:

author: exe
author_rank: Unknown
timestamp: November 23, 2018, 06:08:53 am
content: These are power supplies I use. The transparent one is a kit. The lunch box is the famous "0-30V 0-3A" kit (it can't really handle big currents due to inefficient cooling, but good-enough as an aux supply for biasing). The "big" white box is a custom design 0.7-15V 0-1A based on lt3080. All three are linear.

author: RFDUK
author_rank: Regular Contributor
timestamp: November 23, 2018, 08:33:41 am
content: Made a low cost calibrated noise source for noise figure measurement of low noise amplifiers 8 years ago. Friends saw it and wanted one so I've sold quite a few now. Hope it qualifies for this threadAchieved a temp coefficient of just 0.03dB/degree C and short term and long term stability have proved to be excellent. Covers 10 MHz through 3400 MHz.

author: BFX
author_rank: Frequent Contributor
timestamp: November 25, 2018, 09:22:44 pm
content: Next Isolation transformer

author: nctnico
author_rank: Super Contributor
timestamp: November 25, 2018, 09:30:07 pm
content: A 1kW DC load capable of producing extremely sharp pulses:And ofcourse my current probe:

author: BFX
author_rank: Frequent Contributor
timestamp: November 26, 2018, 09:27:56 pm
content: Diff probe

author: JohnPen
author_rank: Regular Contributor
timestamp: November 27, 2018, 10:13:48 am
content: A few of pictures of my home built Scotties Spectrum Analyser. It was quite a long term construction project and it works very well. The pictures were taken before it was fully completed as there is now changeover relay to switch between 1G/3G and 2G operation. Also there is a Fan installed to improve the temperature stability.

author: bd139
author_rank: Super Contributor
timestamp: November 27, 2018, 10:15:50 am
content: Very nice bit of work on that SABeen meaning to build one of those for years. Don't think I'll ever get the time so may just have to buy one

author: Scratch.HTF
author_rank: Regular Contributor
timestamp: July 13, 2021, 02:05:21 am
content: I've built an AC series load limiter for testing things under repair to reduce the possibility of catastrophic failure:http://github.com/brycecherry75/SeriesLoadLimiterThe case I used was a bit small, but everything fitted in OK - the rocker switch on the side switches the load (not controlled by the Arduino sketch) while the rocker switch on top is used for bypassing the current limit and the green LED is used to indicate that the load is enabled (which will flicker/dim when peak current is being limited and is faster than the LCD display) and finally, the pushbutton is used for configuring the unit (and refreshing the LCD when back EMF countermeasures are enabled should back EMF (even though I took precautions) cause it to blank).

author: Bud
author_rank: Super Contributor
timestamp: July 13, 2021, 03:11:31 am
content: HF Antenna tuner.

author: Bud
author_rank: Super Contributor
timestamp: July 13, 2021, 03:26:00 am
content: GPIB / USB adapter.

author: pqass
author_rank: Super Contributor
timestamp: July 13, 2021, 06:01:09 am
content: Soldering Station for Weller PES51 ironChips in CW order: LM358, LM329 (zener), DIP resistors, ATMEGA328, ULN2003 clone, HEF4017On back: LM7508, IRF640Notables: Uses 20V@3A laptop power brick. 7-segment display shows set temp. (°C) as the rotary encoder is turned then current temp. when stopped.4W into 4ohm stereo amplifier for 2-way bookshelf speakers for desktop computer audio dutyBased on this designhttps://sound-au.com/project113.htmbut with darlington transistors.Notables: I accidentally shorted one of the transformer secondaries and burnt the enamel coating. I ended up spending a few hours rewinding it for just one ±12VAC secondary. I won't make that mistake again.

author: BrokenYugo
author_rank: Super Contributor
timestamp: July 13, 2021, 07:00:41 am
content: I don't need no stinking RF signal generator, at least not to peak a 455khz IF strip.

author: tautech
author_rank: Super Contributor
timestamp: July 13, 2021, 07:55:36 am
content: Nothing clever, special or flashy but knocked together totally from stuff just lying around....the indispensable dim bulb tester:

author: toli
author_rank: Frequent Contributor
timestamp: July 13, 2021, 08:08:12 am
content: Dummy load for audio amplifier testing, and a measurement pre-amplifier for noise/distortion measurement at <100KHz.(more info here:https://tolisdiy.com/2021/03/30/compact-stereo-dummy-load-for-amplifier-testing/)(more info here:https://tolisdiy.com/2021/01/30/audio-measurement-pre-amplifier-part-5-updated-ver1-1/)

author: pcprogrammer
author_rank: Super Contributor
timestamp: July 13, 2021, 11:10:27 am
content: Not really using it but made a spectrum analyzer for a friend of mine. His hardware is a bit more robust and powered from a separate power supply. For development I used this." alt="" class="bbc_img" />It runs on a STM32F103 and loads the data via usb to the computer. The ADC is 16bits 100Ksmps. (ADS8321) It sits on the module on the high legs. This is part of some radar equipment my friend had a bunch of lying around.On the computer it works within a browser. Needs a special usb driver under linux to run it, to be able to go full speed. Also made a scope based on it. Other screen captures are on my laptop which is parked out of the way since I bought a new PC.Still planning on improvements, but other projects came by and there is not enough time to do them all(The FNIRSI-1013d reversal, which is a possible prelude for a follow up of the analyzer)

author: Andrew_Debbie
author_rank: Frequent Contributor
timestamp: July 13, 2021, 03:27:15 pm
content: AMB labs σ22 +/- 30VDC low-impediance low-noise linear power supply. I bought the main PCB from AMB.https://www.amb.org/audio/sigma22/I just finished it today. Ripple is below what I can measure with my cheap bench DMM. I guess I need a better meter.I started this project in 2016!Front and Rear panels with FrontPanelDesigner and fabricated by Schaffer AG.The Bulgin momentary switch on the front panel connects to my debounce / latch / relay driver board. That connects to an off-board 5A crydom zero-crossing relay.The relay driver board also has a high temperature shut down, which turns on the fault LED. The σ22 board has no current limiting or thermal limits. The only other protection is the line fuse. (fuses on both L and N for safety)

author: duckduck
author_rank: Frequent Contributor
timestamp: July 14, 2021, 12:51:43 am
content: I usethreefourpieces of equipment that I've built myself. None are my own invention.I made a capacitor discharger following the plans from Mr. Carlson's Lab (https://www.patreon.com/MrCarlsonsLab). I like to work on vacuum tube guitar amplifiers and voltages inside these can be several hundred volts DC. I use this tool to safely discharge the capacitors before starting work on an amp. Plans are super-double-secret for patrons only, but I'm pretty sure these devices have been made by hobbyists for decades. There are two LEDs on the top. One will light up until all of the angry pixies have calmed down. There are two probes for the capacitors and two banana plugs for plugging into a DMM if one is motivated to watch the voltage go down. You can tell that I built this before I bought Kapton/polyimide tape. I should modify it to include a buzzer so that I can keep my eyes on the probes.I made a tool to measure the plate voltage or plate current on a vacuum tube (can be reconfigured for either) in an amplifier without taking the amp apart. The tube is unplugged and then this device is plugged into the amp tube socket and then the tube is plugged into the socket on the other side of the plug (should be obvious from the picture). The banana plugs are plugged into a DMM to measure mA or DCV. This is used (mainly) to help me set the bias on power amplifier output tubes. I really need to build a second one of these so I can measure two tubes at once. This is based off of a schematic created by YouTube's Uncle Doug. Here's the episode:Finally,I made a light bulb current limiter. I have a selection of incandescent bulbs of various wattages that I use depending on what I'm testing. I use the limiter along with a variac and a KILL-A-WATT (A/C current meter) when I'm powering up an amp for the first time after messing with its guts. This can help prevent stupid mistakes from becoming expensive mistakes. Plans are pretty much obvious and also very easy to find via a web search.Lastly, I built the Elliott Sound Products (Australia!) P86 Miniature Audio Oscillator. I built it from the PCB. I did a hack job but it works very well. It's super useful for testing audio equipment away from the bench. BTW, Rod Elliott responds quickly to emails (from customers, at least). His PCBs are INCREDIBLY well documented and supported. If you are looking for very neat audio projects I HIGHLY recommend ESP. No relation, just a happy customer.https://sound-au.com/project86.htm

author: bsfeechannel
author_rank: Super Contributor
timestamp: July 15, 2021, 12:03:59 am
content: My Wien bridge oscillator. 20 Hz - 20 kHz in three ranges. 0 - 20 Vpp, 600 Ω output.After I mounted it on perf board (which I hate, by the way), the idea was to etch a proper PCB for it. That was almost a decade ago. Talk about procrastination.

author: ccktek
author_rank: Regular Contributor
timestamp: November 02, 2022, 07:16:14 pm
content: (Stretching the meaning of “using now” a little.)Upper photo:BC band generator (1959)Oscilloscope (1961)Variable AC and +/-DC power supply (1973) on top of1.3GHz generator (1976)Oscilloscope (1976)Sound level meter (1980)Lower photo:Trombone air flow meter (2019) on top of4-output power supply (1988)Fast square wave pulser adapter (2017) on top ofFocal plane shutter tester (1997) on top ofWow and flutter meter (1998) andLow distortion audio generator (2019)Semiconductor curve tracer (2021)

author: themadhippy
author_rank: Super Contributor
timestamp: November 03, 2022, 02:14:37 am
content: just a few bitsfirst of the signal generator,using a genuine icl 8038next up the dual power supply, must get some decent labels,but i been saying that for several yearsAs the transformer had multiple taps it also powers the signal generator and has a 18-0-18 v AC output around the backAnd finally on the test gear,the odds and sods.top left logic pulse generator, single shot or continuous ,below that a frequency counter,and as it used an ardunio and only 1 line of the lcd it seemed silly not to add in a capacitor meter.And next to that 8 leds in a box ,very handy for rough checking stuff were firing up the pc for the logic analyser is over kill.With that lot ,amongst other things,i managed to throw a decent stereo togetherphono pre amp and power supply ,the silver box has been painted black . 3 channel amp ,the third channel is for a sub , the case is from a dead 70's tuner and the leds aint that bright off camera,they give a nice glow through the painted scouring pad thats behind the grill . And the pre amp,old skool meets new, ardunio does the magic of controlling the 4 input relays and the 8 relays for the ladder attenuator,no scratchy volume pots here,just the clickyness of a rotary encoder.

author: xrunner
author_rank: Super Contributor
timestamp: November 03, 2022, 02:49:51 am
content: A couple of RF power meters of my own design based on Analog Devices AD8307 and AD8310 log amps.

author: Grandchuck
author_rank: Super Contributor
timestamp: November 03, 2022, 03:39:47 pm
content: Here is a simple but useful oscilloscope preamplifier. It has 40 dB gain and a bandwidth near one MHz. It needs shielding and that is my next soldering project. I will use double sided PC board material.Shielding worked a treat.

author: kripton2035
author_rank: Super Contributor
timestamp: November 03, 2022, 06:40:35 pm
content: of course my shorty-with-display ! details on the link in the signature...IMG_0686.jpg(1702.48 kB. 4032x3024 - viewed 354 times.)

author: kripton2035
author_rank: Super Contributor
timestamp: November 03, 2022, 06:41:38 pm
content: also jay-diddy-b esr meter adapter, I made a digital one

author: jord4231
author_rank: Regular Contributor
timestamp: November 05, 2022, 08:05:10 am
content: Signal tracerOscilloscope component tester before and after adding a volt meter

author: Andrew_Debbie
author_rank: Frequent Contributor
timestamp: January 15, 2023, 09:20:58 pm
content: Battery powered Buck-Boost --> linear power supply powering a 455kHz signal generator.The signal generator is from an old magazine article. The power supply is my design. I've built two of the power supply modules. The one in the photo is 5V and 3.3V. The other runs at 9V paired with a 5V linear regulator.These 50x100mm modules mount on a 100x100mm plate. I've got several other of these little 50x100 modules in work.

author: fourfathom
author_rank: Super Contributor
timestamp: January 15, 2023, 10:19:20 pm
content: I've got a bunch of homebrew test gear. The photo shows a 10W RF attenuator, a resistive 4-way splitter, and a Time Interval Counter (TIC) of my own design and build. The TIC has this inside:A 100MHz internal clock (a PLL inside a gate-array), which can be locked to either an internal 10MHz TCXO, or an external reference (such as the Bodnar GPSDO I usually use).Four inputs, AC or DC coupled, 50 Ohm or 10 Meg termination, >100 MHz input response. Any of the four inputs can be used as the external reference clockSelectable divide-by-ten prescaler, settable 32-bit divider for each of the four measurement channels, Rising/falling edge selectionTimestamp capture for each measurement channel, 10 ns resolution. Event / Interval / Period / Frequency calculation and reportingAn internal NCO / mixer / filter which provides high-resolution measurements of narrowband high-frequency inputs (example: < 10 milliHz resolution of a 10 MHz input at a 10 Hz measurement rate)OLED display (the photo shows the screensaver, a scrolling sinewave to reduce OLED pixel burn)USB "serial port" control and reporting interface to external programs. About 50 measurements per second max reporting rate (serial port limitations)The chart photo shows a frequency vs temperature measurement I made this morning, testing the TCXO in a ham transceiver. The chart shows a frequency of about 100 Hz; this is actually the difference between the 25 MHz TCXO and the internal NCO. This shows that the TCXO frequency is varying by about 3Hz. I used a modified "Reptile Incubator" with a homebrew controller as a temperature chamber. Notice the frequency "retrace" as the temperature cycles up and down.I've got lots more homebrew gear, but I had these photos handy.

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: January 16, 2023, 06:30:12 pm
content: QuoteVery nice GPIB adapter. What design is that? It looks similar to the Galvant design.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: January 17, 2023, 01:48:39 am
content: DDS function generator based on AD9833, VCA822, TLV5618, Raspberry Pi Pico. Controllable by SCPI and a UI, has a bonus +/-3V programmable voltage source with 12 bit resolution. Attenuator down to -60dB.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 17, 2023, 02:05:49 am
content: 8 channel thermometer. DS18B20 as a sensor. Raspberry Pi Pico (clone) inside.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 17, 2023, 02:10:14 am
content: High Resistance Standard. For calibration of a picoammeter that I'm developing. Upper red banana jack was replaced with BNC later.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 17, 2023, 02:16:20 am
content: Test fixture (Faraday cage) for electrometry stuff. I can measure high resistance (100 Meg with HP 34401a for example, and higher), leakage current ans son on. This boix is also intended for my picoammeter.P.S. D-Link hub is a very important for such measurements

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 17, 2023, 02:59:01 am
content: Quote from: dobsonr741 on January 17, 2023, 01:48:39 amNice generator! I like it!

author: HarryDoPECC
author_rank: Regular Contributor
timestamp: January 17, 2023, 05:30:24 am
content: I'm entering in the"Essential to Me but Unlikely to be Useful to Anyone Else, Anywhere"categoryWang 300 Series Keyboard TesterBefore opening the logic case to chase a non-existent fault among four hundred transistors and 1k diodes, all 60 years old, it's a good idea to make sure that the ancient transistors and diodes in the keyboard and display are not the problem.Wang 300 Series Core Select/Drive TesterSetting up the MSO to check that the right half-selects are being activated onto the core plane is tedious and it's useful to be able to check that the decoding logic is working and that the drive currents are about right. The half selects flash past, Lord Knows how they did this in the day with 2 channels, 1 trigger and no storage.....

author: fourfathom
author_rank: Super Contributor
timestamp: January 17, 2023, 06:41:00 am
content: Quote from: HarryDoPECC on January 17, 2023, 05:30:24 amYeah, I know what you mean! It's fun though, isn't it?

author: JimKnopf
author_rank: Frequent Contributor
timestamp: January 17, 2023, 11:22:18 am
content: I use a selfmade resistor decade from time to time. I once bought one from a well known chinese selling platform that looked like it was from Mao era. It was too big and not accurate enough for my purposes.I built it from 9 (later one with 10) thumb wheels. One with old-style resistors and one with SMD resistors.I also like to use the Retro-Chip-Tester (RCT). A do-it-yourself project. You can buy the pcb at 8bit-museum.de. The other components you have to get yourself. You can eventest and burn very old chips with it.

author: jonpaul
author_rank: Super Contributor
timestamp: January 17, 2023, 12:19:28 pm
content: Popular Electronics Super Audio Sweeper restoration of 1973https://worldradiohistory.com/Archive-Poptronics/70s/1973/Poptronics-1973-10.pdfStill working after 50 years!Your thoughts appreciatedJon

author: alanep
author_rank: Contributor
timestamp: January 18, 2023, 07:53:03 am
content: A homemade audio distortion analyser (10Hz - 100KHz). The tracking notch filter is based on the Tektronix AA5001 and everything else is my own design. I built it back in 2003 with a few subsequent updates/changes - the last was a firmware update to the controller Nov 2022.It uses average detection, RMS calibrated so it hasn't kept up with the latest standards. It has a residual of about 0.0014% with a 0.5V RMS 1KHz test signal from a clone of the Tektronix SG505.It uses NE5534 opamps in the main signal path and the tracking notch filter. The tracking notch filter is a very special design by Bruce Hofer who went on to form Audio Precision (with other ex Tektronix employees). It uses Vactrols (VTL5C4) for the notch filter frequency control with very low distortion. VTL5C4s are still available but for the last 30 years, they've been made to a different cadmium sulfide chemistry and have much higher distortion. So, this unit can't easily be replicated i.e. the VTL5C4 you buy now won't be suitable (I bought mine back in 1990s). This might have been one of the reasons Bruce Hofer went to a state variable filter with "MDAC"s (major frequency control) and FET for fine frequency control in the Audio Precision equipment.When I was designing this unit, I've found that the rotary mechanical switches' non-linear contact resistance can introduce measurable distortion when passing the signal. So I used a Motorola MC68705P3S single chip microprocessor to scan the selection switches (with DC/pullup resistors) & then to control the various relays that actually pass the signals. These relays have high quality contacts which are far better than the readily available rotary switches.Being a "one" off, the unit was built using veroboard. With careful layout & using ground protection tracks/planes, it achieved a noise floor of -114dBm (shorted input and with 80KHz B/W filter). Please note, this unit's input is unbalanced and thermal noise is lower compared to an electronically balanced input stage (with similar devices/topology). I should explain that whilst a balanced input will have better common mode rejection (for hum/noise), it does have one downside i.e. the thermal noise contribution of the two inputs. A designer has to work much harder for lower thermal noise in a balanced input topology...It also includes a monitor speaker for identifying obvious problems but for better understanding of the type of distortion, you can't beat looking at the function O/P on an oscilloscope.Anyhow, here are the pictures:

author: fourfathom
author_rank: Super Contributor
timestamp: January 18, 2023, 08:11:14 pm
content: Quote from: alanep on January 18, 2023, 07:53:03 amI am very impressed. Nice retro-looking meter, too!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 18, 2023, 09:06:00 pm
content: To varying degrees of "using now":Bench supply (linear, +/-20V 10A or so)GPIB-serial adapter -https://www.eevblog.com/forum/testgear/tds460-hardcopy/msg2950524/#msg2950524High current supply/load (switching)Lead acid battery charger, 24V 5A -https://www.seventransistorlabs.com/Images/100WPowerSupply24V.jpgLoad dump, 24V -https://www.eevblog.com/forum/projects/24v-load-ballast/msg4002922/#msg4002922Electronic load, 500V 4A -https://www.seventransistorlabs.com/Images/ActiveLoad2.jpgIsolation transformer (240V 15A)Desktop and bar style LED lights (50-100W) -https://www.seventransistorlabs.com/Images/LED_Light.pnghttps://www.seventransistorlabs.com/Images/LED_Light2.pngDigitally controlled 4 channel LED supply -https://www.seventransistorlabs.com/Images/QuadController2.jpgEMI testing networks:- FCC Part 15 style, 2 and 3 channel -https://www.seventransistorlabs.com/Images/LISN1.jpghttps://www.eevblog.com/forum/projects/another-lisn/msg3905765/#msg3905765- custom 20MHz+ LISN, 6 channel -https://www.seventransistorlabs.com/Images/LISN_Built.jpg- automotive style 2 channel -https://www.eevblog.com/forum/projects/high-current-lisn/msg4576645/#msg4576645- Ethernet 2-pair CDN -https://seventransistorlabs.com/Precompliance/Images/EthernetBreakout2.jpgCurrent limiting electronic fuses (10A linear, 20A bidirectional switchmode) -https://www.seventransistorlabs.com/Images/Fuse2.jpghttps://www.seventransistorlabs.com/Images/SwitchingCurrentLimitUnits.jpg20m shortwave receiver -https://www.seventransistorlabs.com/Radio_20m/index.htmlEnjoyTim

author: ElectricPower
author_rank: Frequent Contributor
timestamp: January 19, 2023, 06:53:17 am
content: Her is my little mancave:

author: fourfathom
author_rank: Super Contributor
timestamp: January 19, 2023, 07:01:26 am
content: Quote from: ElectricPower on January 19, 2023, 06:53:17 amOK, that's just scary. How can any workbench be *that* neat???But I do like the instrument "bookcase". I definitely have to make something like that.

author: ElectricPower
author_rank: Frequent Contributor
timestamp: January 19, 2023, 08:29:30 am
content: Quote from: fourfathom on January 19, 2023, 07:01:26 amBecause I cleaned properly before I took the pictureIt's just a shep bookcase from an sheap Norwegian store. I think i gave around 10 USD for it

author: Calambres
author_rank: Frequent Contributor
timestamp: January 19, 2023, 11:49:02 am
content: OK, I'll biteThe electronic part of my man cave:Detailed view of my homemade equipment, all of them used quite often:Description:1 - The ever ubiquitous Dim Bulb Tester2 - Resistor decade box3 - 30V max / 200mA to 10A / 60W DC load4 - Differential Circuit breaker (GFCI) tester5 - Square and sinewave analog signal generator (http://pisotones.com/GF/GF.htm)6 - Pi RF attenuator and dummy antena7 - RF amplifier8 - 8A - 8V to 22V DC short protected and current adjustable power supply9 - (under the fan) Capacitor Leakage Tester (http://pisotones.com/CLT-R/CLT.htm)10 - 230V-230V 100W Isolation transformer11 - Capacitor outer foil detector (http://pisotones.com/Articulos/DirCaps/DirCaps.htm)12 - 200V - 100W - 0A to 1.5A DC load (http://pisotones.com/CF-DC/CF-DC.htm)13 - Mr. Carlson's low voltage capacitor leakage tester14 - +/- 0V to 32V - 1A symmetrical power supply...and out of sight, a transistor curve tracer:There are some other minor projects here and there... I've been making DIY electronics for decades now!

author: Gyro
author_rank: Super Contributor
timestamp: January 19, 2023, 12:34:45 pm
content: Quote from: ElectricPower on January 19, 2023, 06:53:17 amJust a note that we have a long 'show your workbench / mancave' thread for where the general work area outweighs the home-made equipment...https://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/

author: BillyO
author_rank: Super Contributor
timestamp: January 19, 2023, 04:59:44 pm
content: I built this up a couple of months ago. Just a cheap DC-load module in a nice case with an isolated linear power supply and set up for switchable 2-wire/4-wire mode.I use it quite a bit for testing rechargeable batteries and other things. It's a lot easier to use than my Siglent load, so it gets all the small, simple work. Quite surprised how much use I'm getting out of it actually.

author: MathWizard
author_rank: Super Contributor
timestamp: January 19, 2023, 05:11:05 pm
content: Quote from: ccktek on November 02, 2022, 07:16:14 pmHey ccktek, seems you've been at this while LOL. What sort of curve tracer did you make in 2021 ?

author: ccktek
author_rank: Regular Contributor
timestamp: January 19, 2023, 10:29:02 pm
content: MathWizard, thanks for your correct observation and inquiry.https://www.eevblog.com/forum/projects/self-contained-semiconductor-curve-tracer/msg3551423/#msg3551423

author: Zero999
author_rank: Super Contributor
timestamp: January 19, 2023, 10:50:57 pm
content: A dual tracking +/-15V LM317 & LM337 power supply. I've just noticed there should be a centre tap on the transformer in the schematic, but otherwise it's correct.

author: MathWizard
author_rank: Super Contributor
timestamp: January 20, 2023, 03:15:59 am
content: Quote from: ccktek on January 19, 2023, 10:29:02 pmYeah it looks interesting. I've have a couple of old transformers lying around that I plan to use in a real CT.I've made a few little circuits on proto-board over the past few years, that are like my home-made tool box. Like an H-bridge tester for small motors, a TRIAC/SCR tester, an 11M resistor box, a wire tracer/ finder, a RF probe/signal tracer, resistive load testers on boards, etc.I built a copy of an old linear 30V, 1A PSU.Now that I have a bit of money, I need to start making better stuff. Like a better op-amp controlled PSU, a 1/2 way decent curve tracer, and modular high power, high current load tester for some computer PSU's. I need to start looking locally for good transformers and heat sinks. Otherwise I'd have built some better by now along those lines.But I really want to learn some more theory, so I don't just copy exactly another design. But I would try to copy some older stuff like Heathkit.

author: inse
author_rank: Super Contributor
timestamp: January 20, 2023, 06:23:11 am
content: @ MrYakimovYA #36 ReplyDo you need special connectors and cables to handle 100GOhms without compromising the measurements?

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 20, 2023, 10:06:44 am
content: Quote from: inse on January 20, 2023, 06:23:11 amNo, I have no triax cable, so I use just a common coax. The metallic shield, metal case are used as a guard. So I can't see any problem. I tried to draw all these ideas at the attached picture) Where Il@Rl1 - leakage current throught RL1; IL@RL2 - leakage current throught RL2.RL1, RL2 - leakage resistance of input and output coaxs.All ideas had been taken from:https://www.tek.com/en/documents/product-article/keithley-low-level-measurements-handbook---7th-edition

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 20, 2023, 10:12:05 am
content: I use it quite widely. I check the ability of something with linear transformer inside to work from wallet outlet. I also can have a high voltage to check leakage current or measure something above 1G, for example.

author: Njk
author_rank: Frequent Contributor
timestamp: January 20, 2023, 08:16:21 pm
content: It took a time to locate it, but I did. Because of peculiarity of the thing.Compact water-cooled rectifier CWCR-001, of my design. For testing a 12/24V automotive stuff (DC motors, etc.) in the lab. Features:- small form factor, easy to keep when not in use;- 10A diode bridge inside;- ISO 4165 DC output socket.Before use, put it in a jar with cold tap water. Watch the temperature, replace the water when necessary.Machined from an aluminum piece by my best manufacturing partner, a decades ago. Developed some internal rust (stainless screws were not available) but still works.

author: vinlove
author_rank: Frequent Contributor
timestamp: January 20, 2023, 11:35:42 pm
content: AD9850 DDS RF generator kit. This was simple and easy build needing just a soldering iron, wire stripper, plier, nipper and screw drivers.About 5- 7 years ago when I had an old Ten Tec Omni with seized up VFO, this unit connected to the external IF port of the Omni, and drove the TenTec nicely making tons of HF contacts. The TenTec Omni had been sold, but this self built AD9850 DDS VFO controller / RF Generator is still here. It had not been used for few years now. I am planning to build a HF receiver using this kit.

author: amc184
author_rank: Regular Contributor
timestamp: January 22, 2023, 02:31:52 am
content: I built a couple of USB to UART adapters because I wasn't that happy with what I could find off the shelf. One is isolated RS-422, with DC to DC converters to supply the device side. The other is plain UART, with the option of host powered 3.3 or 5V levels, or isolated with a device defined level.Both use a CoreChips SL2.1A as a USB hub and a Holtek HT42B534-1 USB to UART converter. I chose both because they did what I needed and were simple to implement. I used an Analog Devices ADUM1201 for the isolator, and a Sipex SP490 for the RS-422 version. They work well now, but I had to do a couple of spins to get them right, and spent way more time than I should have on a side project - the story of my hobby.

author: Miti
author_rank: Super Contributor
timestamp: January 22, 2023, 04:08:28 am
content: The frequency counter is not used anymore but the others are.1. Universal soldering station, Unisolder designed by Sparkybg. It can take (autodetect) pretty much any iron. This is my main soldering station.2. LC meter for small parts, pF-nF, nH-uH.3. Thermometer, barometer with PIC16F946 and LCD. I designed this to understand better how to use the PICs with LCD drivers and to see how low power I can go. The 300mAh battery lasts about a year and couple of months full change, a reading every 3 seconds.4. Frequency counter 100MHz. It has auto blank zeros, auto decimal point, units indicator, period, etc. All gates and counters, no MCU rubbish. I designed and made this when I was in highschool.

author: BillyO
author_rank: Super Contributor
timestamp: January 23, 2023, 01:46:25 am
content: Just made a set of Thevenin lead today. 14 gauge silicone insulated wire. These will simplify 4-wire measurements / power supplying / loading / etc..

author: py-bb
author_rank: Regular Contributor
timestamp: January 25, 2023, 08:08:08 pm
content: Quote from: Bud on July 13, 2021, 03:26:00 amSchematics and part list please!

author: Bud
author_rank: Super Contributor
timestamp: January 25, 2023, 09:25:48 pm
content: It may not be useful to you, because it was a custom design and would not be supported by the usual computer side software and libraries. I wrote my own for it. And the PIC on the board had a custom firmware that handled communication with only a few old HP instruments that I had at the time, it was not a generic adapter.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 26, 2023, 07:37:41 am
content: My Resistance Set Standard. There are precision soviet union S5-60 (C5-60) and MRH (МРХ) resistors inside. It's in testing stage yet... I'm investigating its specifications))

author: Vgkid
author_rank: Super Contributor
timestamp: January 26, 2023, 09:45:09 am
content: That looks nice. I had plans for a similar idea.Pics of the internals.

author: Njk
author_rank: Frequent Contributor
timestamp: January 26, 2023, 02:41:54 pm
content: Another related things from my museum.1. A combo device that integrates the three functions in the welded aluminum housing:- 6V AC PS for soldering iron;- curve tracer for testing the integrity of a 74xx logic I/Os without having to de-solder the chips from the PCB;- 5V 1A general purpose trimmable DC PS (LM317).Proved very useful for field troubleshooting of a PDP-8/PDP-11 mini-computers at the component level.2. Metal is not the only construction material. Plywood is more eco-friendly one. A wooden PSU of the bench type (left). Don't show it to a firefigther but eventually it made a contribution to public safety. First OnStar automotive boxes were powered from this unit during the development time. Tor trafo + minimalistic design = space saving (convenience). Compare it with a full-blown commercial PCU on the background.3. Sensor board signal simulator. Generates a project-specific pulse patterns from an input sine wave. Lot of 54xx chips. A golden heritage...

author: cgroen
author_rank: Unknown
timestamp: January 26, 2023, 02:57:06 pm
content: Rotorcontroller (Az/El) control for my satellite system (and soon EME system)All done from the bottom, hardware and software (except the power drivers, these are plugin modules as I had expected they could at some point go "puff", so far they have not)(more pics etc:https://www.moonbounce.dk/hamradio/ham-radio-current-systems/rotorcontroller.html)

author: Njk
author_rank: Frequent Contributor
timestamp: January 26, 2023, 03:56:00 pm
content: Quote from: cgroen on January 26, 2023, 02:57:06 pmI like the antenna motor drive you're using. How frequently you have to service it?

author: cgroen
author_rank: Unknown
timestamp: January 26, 2023, 04:09:52 pm
content: Quote from: Njk on January 26, 2023, 03:56:00 pmThanks,so far it is running flawlessly! Current draw was a bit higher when we had -11 degC, but that was to be expected (approx 1000 mA compared to approx 400 mA).Have had it in use for 5 months now (heavy use, every day)

author: py-bb
author_rank: Regular Contributor
timestamp: January 27, 2023, 10:59:26 pm
content: Quote from: Bud on January 25, 2023, 09:25:48 pmIt may still be please! I have some LeCroy stuff and software I wrote with serial ports, not realising that it takes 700 seconds to dump all the channels at the thing's top baud rate - so... I'd really love a look

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 28, 2023, 07:25:42 am
content: Quote from: Vgkid on January 26, 2023, 09:45:09 amA bit of horror is inside. As I said earlier I'm testing it. And I'm collection a bunch of notes what to fix. A lot of wires, for example, must be tied to each other with a nylon tie. Some solder connectios are a little ugly. And I'm going to replace 100 kOhm and 1 MOhm decades with a more stable S5-60 (с5-60 in Russian) resistors instead of MRH (МРХ in Russian) type. I'm awaiting them via the post from another city.

author: jasonRF
author_rank: Regular Contributor
timestamp: January 29, 2023, 12:39:53 am
content: This is a ~6 dB, ~5 MHz amplifier I built with selectable 50 Ohm or "0" Ohm output impedance. I originally designed it to use with the 100 kHz signal generator built into my Picoscop 2204a, which has a 600 Ohm output and is limited to +/- 2V output. It is AC coupled on input and output and is almost exclusively used for sinusoids. My original design used opamps and would have been simpler and better, but this was more funjason

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 29, 2023, 03:38:43 am
content: Quote from: jasonRF on January 29, 2023, 12:39:53 amNice work! It looks so nice! Could you tell me what is its noise level?

author: Bud
author_rank: Super Contributor
timestamp: January 29, 2023, 06:43:13 am
content: Quote from: py-bb on January 27, 2023, 10:59:26 pmI made mine in 2012, here is a link to the author's web page, seems he released several updates since then.But he said the speed is 57600 baud.http://dalton.ax/gpib/

author: Bud
author_rank: Super Contributor
timestamp: January 29, 2023, 07:14:58 am
content: A project from 2003, a dual audio tone generator 700 Hz and 1800 Hz to check intermodulation performance of Ham radio transmitters (design from an ARRL Handbook of the era)

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: January 29, 2023, 08:10:40 am
content: HP 3325BHP 8904ATektronix 2445Tektronix 2465Keysight E3620AR&S CMU200keithley 197aFLUKE 87hakko FR-801 smd rework stationhakko 850bquadtech 1659 rlc digibridge

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: January 29, 2023, 09:23:46 am
content: Quote from: DavidAzulay5000 on January 29, 2023, 08:10:40 amWow! What a nicehomemadeequipment!

author: BillyO
author_rank: Super Contributor
timestamp: January 29, 2023, 05:37:16 pm
content: Quote from: MrYakimovYA on January 29, 2023, 09:23:46 amI was thinking the same thing.

author: DavidAzulay5000
author_rank: Regular Contributor
timestamp: January 29, 2023, 06:06:48 pm
content: Quote from: BillyO on January 29, 2023, 05:37:16 pmI bought most of the my equipment broken .i repaired and calibrated itI enjoy it the mostto repair measuring equipment

author: shapirus
author_rank: Super Contributor
timestamp: January 29, 2023, 06:35:16 pm
content: This is a voltage reference based on a well-known Chinese "LM399" module which actually appears to be staying pretty stable over time. How precise the numbers that are hand-written on it are is quiestionable, but they appear good enough and they can always be verified when there's a chance to use a precision voltmeter. Most importantly, it can definitely be used to check if the DMMs are still all right, which is its primary job.Inside is a linear power supply and mode selection circuitry that uses relay contacts where a jumper was used on the module's pin header to select one of the six output voltages.Usage:And this one's used literally every time I need to try something out on a breadboard or quickly power something up otherwise.Nothing fancy, just an isolated transformer -> bridge -> caps -> one of those well-known Chinese DC/DC modules.

author: jonpaul
author_rank: Super Contributor
timestamp: January 30, 2023, 02:10:57 am
content: Unearthed in the # 3 archive, covered in dirt , unused in 30 years.1980s DIY 3 wide Tektronix plugin TM500 tester PSU, like TM503 but no cage or rails just the PSU.NPN/PNP on floating HS, 56 pin genuine AMP card edge connectors are gold plated and spring floating.Your thoughts appreciated!Jon

author: jasonRF
author_rank: Regular Contributor
timestamp: January 30, 2023, 12:15:55 pm
content: Quote from: DavidAzulay5000 on January 29, 2023, 06:06:48 pm

author: tomud
author_rank: Regular Contributor
timestamp: February 05, 2023, 12:45:57 am
content: My old case design for Chinese 150W Constant Current Electronic Load 60V 10A3D Printing Case Design:https://www.thingiverse.com/thing:4328521

author: rfclown
author_rank: Frequent Contributor
timestamp: February 05, 2023, 04:01:32 am
content: Rubidium 10 MHz.

author: coppercone2
author_rank: Super Contributor
timestamp: February 05, 2023, 11:06:57 am
content: Small 1A variac. Has fuses and an IEC connector on the back. Needs one more switch on the back, so its possible to isolate the primary when plugged in (I will probobly add a switch + iec this spring). The vents are painted steel grate. One of a few that I have built. But this one is mainly used as a portable source that goes back on the shelf when not in use. And color coding the binding posts is a priorityI also always wanted to lay in the inside with metal, maybe nickel silver sheet. And a indicator lights for powered and output (which will only work for high settings). Plenty of room for a few things anyway, but that one is not getting meters.

author: Kosmic
author_rank: Super Contributor
timestamp: February 05, 2023, 02:14:02 pm
content: Quote from: tomud on February 05, 2023, 12:45:57 amMighty good job with the enclosure, I'm impressed

author: rfclown
author_rank: Frequent Contributor
timestamp: February 05, 2023, 03:40:37 pm
content: Quote from: ccktek on November 02, 2022, 07:16:14 pmNot that's something I don't have on my bench. Where do you sent it for calibration? I do have a trombone line, but I couldn't find it to take a picture, so I took a picture of a dial phase shifter (same function) and a tuner along with my cornet and trumpet mouthpieces. I don't have any mouth piece to N adaptors though.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: February 05, 2023, 07:14:54 pm
content: 5 1/2 digit Autoranging DC voltmeter for 150mV...250V. Built with ADS1263. SCPI control over USB.

author: jasonRF
author_rank: Regular Contributor
timestamp: February 06, 2023, 12:59:00 am
content: Quote from: MrYakimovYA on January 29, 2023, 03:38:43 amMy scope says about 210uV RMS. This is with 50-Ohm feedthrough on the scope, with the 20 MHz bandwidth limit turned on, and with the amplifier set to 50-Ohm output impedance and the volume control set to max. The noise level of just the scope is about 160uV RMS with the 20 MHz limit, so the amplifier is at the limit if what the scope can see. By the way, the scope is a Picoscope 5244B, and I was running it in 16-bit mode at 62.5 MS/s at the most sensitive scale (which is only 2mV/div).Jason

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: February 06, 2023, 01:29:18 am
content: My Unisolder with Pace Accudrive handle that I use almost exclusively.

author: tomud
author_rank: Regular Contributor
timestamp: February 06, 2023, 03:56:04 pm
content: Vacuum pick and place tool controlled by a foot switch.Electronics built from what I had in stock (universal board, AT Mega microcontroller, etc.). It has several operating modes, adjustable pump speed, valve opening time, etc.

author: MiroS
author_rank: Regular Contributor
timestamp: February 07, 2023, 12:33:58 pm
content: Quote from: MrYakimovYA on January 28, 2023, 07:25:42 amI fully agree.

author: tomud
author_rank: Regular Contributor
timestamp: February 07, 2023, 04:18:37 pm
content: Quote from: Kosmic on February 05, 2023, 02:14:02 pmThank you for the kind words. I'm not an expert in designing in CAD programs, just an electronics engineer and a programmer. But I try to do projects for a 3D printer as best as I can and I'm still learning.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: February 14, 2023, 08:50:13 pm
content: A portable DCV/DCI/OHMs programmable standard (left) for the "Russian Cal Club" and an upcoming desktop version for home use (right). Both are powered by selected AD5791+LM399 after 5.2 years of electrical/thermal training.

author: shapirus
author_rank: Super Contributor
timestamp: March 04, 2023, 07:12:32 pm
content: Yet another dummy load™This time made for the specific purpose of selecting the least crappy USB cables or USB chargers from those lying around that accumulated over the years.0..2A adjustable constant current.

author: Edison
author_rank: Frequent Contributor
timestamp: March 17, 2023, 09:54:34 am
content: Hello, I haven't been here for a long time and I completely forgot about the request to create a thread with my creations, so at least add something here - the latest work is an AC regulated power supply 30V15ASome photo of the gauges adjustment, done and here it rests with other creationsNice day 🙂 Tom

author: shapirus
author_rank: Super Contributor
timestamp: March 17, 2023, 09:58:37 am
content: Quote from: Edison on March 17, 2023, 09:54:34 amBeautiful.Will you be willing to share the schematics?

author: Edison
author_rank: Frequent Contributor
timestamp: March 17, 2023, 10:17:53 am
content: I will also add one piece of quadruple voltmeter +/- 200V DC, the gauges are galvanically isolated and can thus be connected anywhere in the device under test, I haven't removed the protective film yet, because I don't have the anchor ready - so I don't scratch it.I still have enough in stock, so I'll throw in something sometimes 🙂

author: Edison
author_rank: Frequent Contributor
timestamp: March 17, 2023, 10:43:45 am
content: Hi, there is nothing complicated about it, a regulation transformer is used at the input and a large toroid at the output - I needed another AC source and so I quickly built it from what I had at home, I originally thought about regulating the current, but in the end I didn't do it.

author: Jester
author_rank: Frequent Contributor
timestamp: March 17, 2023, 11:47:31 am
content: I'm using it this morning, 19bit AC/DC load, mostly use it in AC mode. 250V, 40A

author: Edison
author_rank: Frequent Contributor
timestamp: March 17, 2023, 12:34:14 pm
content: Well used HP case, unfortunately these boxes do not fit deep into my workplace👍 beautiful work 👍

author: jasonRF
author_rank: Regular Contributor
timestamp: June 17, 2023, 03:34:27 pm
content: This is a very simple low-voltage differential probe I made a while ago, mostly to use at audio frequencies, so is just built with a TL052 with some 0.1% 100k resistors. I had it open today to check which op amp I used so decided to take a picture. The front-panel switch is to engage a 40 kHz 2nd-order Butterworth low-pass filter (very useful when measuring outputs of some class-D amplifiers). I measure 50+ dB CMRR in the audio band. It frees up a channel on my 2-channel scopes, so is pretty useful.jason

author: Martin72
author_rank: Super Contributor
timestamp: June 17, 2023, 07:12:50 pm
content: Not in use now, but in progress:Power inductor checker, inspired by:http://elm-chan.org/works/lchk/report.htmlI designed the board and made some changes, the first test showed that some improvements are still necessary.When I have them on the way, a separate thread will follow.

author: Aldo22
author_rank: Super Contributor
timestamp: June 17, 2023, 07:59:52 pm
content: My first, handmade, cheap adjustable power supply.

author: ccktek
author_rank: Regular Contributor
timestamp: June 19, 2023, 06:52:31 pm
content: Latest addition to the brood:Variable isolation transformer (2023)https://www.eevblog.com/forum/testgear/show-the-homemade-equipment-you-are-using-now/msg4498885/#msg4498885

author: fable
author_rank: Regular Contributor
timestamp: June 30, 2023, 07:43:03 am
content: Here are some of the tools i have made and use every dayFirst picture from top to bottomDummy LoadPSU ac/dcvacuum pump pickup tooltriple soldering iron controller2. PSU 2x24v 2A3. Soldering iron and desoldering gun controller4. Differential probe

author: KungFuJosh
author_rank: Super Contributor
timestamp: June 30, 2023, 01:22:34 pm
content: This is my vacuum tube curve tracer.In my current unit, I added a step up converter for the heater voltage. Now I can run heater voltages at 20V easily (or higher, but I don't have any need for that).

author: py-bb
author_rank: Regular Contributor
timestamp: August 03, 2023, 05:06:25 am
content: Quote from: MiroS on February 07, 2023, 12:33:58 pmBut totally worth posting - I learn a lot from just seeing how some of these are assembled.Never be afraid to post a monstrosity, if we only posted perfection there would be no posts!

author: Hexley
author_rank: Regular Contributor
timestamp: August 03, 2023, 03:56:42 pm
content: This device tests batteries of various types -- button cell, AAA, AA, C, D, and N; coin cell lithium; and 9 volt packs. It supports battery chemistry of alkaline or NiMH types for most cells.The knob selects the cell size and chemistry, then is clicked to start a load test with the appropriate current. The voltage under load is measured, and the display shows "New/Good/Weak/Dead" according to the corresponding voltage threshold. The estimated charge level is displayed, as is the voltage under load.It is built around an adjustable current sink with a range of 10 uA to 200 mA, controlled by a small ARM Cortex processor that also handles the rotary encoder input and LCD output.The battery holder is a "BF-2A", found on Banggood. Henrik Jensen (forum user HKJ) put me on to it.