hybridfree/eevblog-posts huggingface dataset:
French Weekly Electronics Magazine in newspaper format - Page 1
Forum section: electronics / beginners

author: TK
author_rank: Super Contributor
timestamp: April 25, 2018, 11:30:46 pm
content: When I was a teenager I used to buy and read a weekly electronics magazine that came in newspaper format and it had lots of DIY electronics projects. Does anyone know the name of the magazine? I used to buy it in Argentina, translated to Spanish, but I am sure it was a French Magazine.

author: TK
author_rank: Super Contributor
timestamp: April 25, 2018, 11:36:13 pm
content: The name in Spanish was Radio Electronica Practica
Frenquency Interference - Page 1
Forum section: electronics / beginners

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: May 27, 2020, 06:10:56 am
content: Here is a spectrum graph of the signal on a VHS tape:https://imgur.com/a/OH5AxWVThe text says that there's interference between the luma and chroma signals, which is shown by the trapezoid things. My question is - what are these trapezoid things on the graph? If the luma signal is 3.4mhz at it's lowest and the chroma signal is 629khz, how is there interference? Thanks in advance.

author: ataradov
author_rank: Super Contributor
timestamp: May 27, 2020, 06:21:42 am
content: There is no way you can have perfectly square and sharp signal, so those edges represent real signal, whose spectrum is a bit wider.3.4 MHz is the lowest for the carrier, not for the whole spectrum.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: May 27, 2020, 05:06:58 pm
content: So because the signal is imperfect, the luma carrier can go from 3.4mhz to 629 khz and interfere with the chroma signal? That sounds like quite the jump.

author: ataradov
author_rank: Super Contributor
timestamp: May 27, 2020, 05:21:19 pm
content: 3.4 MHz is a carrier frequency. The carrier can't jump this much. But the signal has some bandwidth, and the edge of that band may move into 629 kHz range.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: May 27, 2020, 11:12:39 pm
content: I'm still confused. The spectrum shows that the signal has 1mhz between it's minimum frequency and it's maximum. What is the point of the trapezoidal shape around it? Is there some sort of article that I can read to explain this? Thanks.

author: AutogolazzoJr
author_rank: Regular Contributor
timestamp: May 27, 2020, 11:15:39 pm
content: Nevermind, it's because of sidebands.

author: ataradov
author_rank: Super Contributor
timestamp: May 27, 2020, 11:25:07 pm
content: They are not side bands, they are part of the useful signal. Amplitude variation is part of the signal, and it results in a wider spectrum than a regular carrier would. If they were just side bands, you would be able to filter them out, you can't do that without also damaging the useful signal.
Freq /32  for LTC2400 - Page 1
Forum section: electronics / beginners

author: GigaJoe
author_rank: Frequent Contributor
timestamp: February 01, 2018, 05:11:49 pm
content: Hello,I'd like to feed LTC2400 by external frequency, instead internal oscillatorso frequency option would be:153600Hz * 32 = 4915200* 16 = 2457600* 8 = 12288004.9152Mhz - seems most popular ...2 questions:1: if I use a quartz instead ready oscillator , can anyone suggest a chip to build a oscillator , preferably to adjust freq if possible .2: chip as divider: /16 or programm. /32Thanks in advance ..

author: danadak
author_rank: Super Contributor
timestamp: February 03, 2018, 02:14:00 am
content: http://www.cypress.com/products/clocksWhat range of freq do you need to adjust frequency ?Regards, Dana.
Frequency above 5 kHz not showing on Oscilloscope  - Page 1
Forum section: electronics / beginners

author: Shanza Baig
author_rank: Newbie
timestamp: July 31, 2024, 04:42:56 pm
content: Hello,When I set the frequency of 5 kHz or below using the function generator, the oscilloscope is able to display the correct reading on screen. However, when I increase the frequency the value on screen reduces below 5 kHz and does not show the correct value.Can you please guide me how can I see the correct value of frequency on oscilloscope. And also, if I have set 10 kHz then it's actually this value or the one the oscilloscope is showing is correct??

author: themadhippy
author_rank: Super Contributor
timestamp: July 31, 2024, 04:59:34 pm
content: might be usefull to tell us the make and model of the oscilloscope as theirs a few to guess from.

author: radiolistener
author_rank: Super Contributor
timestamp: July 31, 2024, 06:58:07 pm
content: Probably you're didn't adjusted horizontal time scale to fit with more high frequency. If you're using some Chinese toy instead oscilloscope it going to be more critical, because Chinese toys have very short sampling buffer and unable to see high frequency at slow horizontal scale.

author: Aldo22
author_rank: Super Contributor
timestamp: July 31, 2024, 07:54:13 pm
content: Quote from: radiolistener on July 31, 2024, 06:58:07 pmEven the cheapest china scopes have an auto-button that makes the correct settings for you.But without more information from the OP we can't narrow down the problem.

author: richnormand
author_rank: Unknown
timestamp: July 31, 2024, 10:40:19 pm
content: First, hook up you signal generator to an audio line amp input (below half a volt max) and sweep it from 5kHz to 20 kHz and listen to the sound.If the output drops rapidly before 10kHz the generator might be defective. After that, as the frequency goes up to 10 kHz, its your ears, depending on your age.Second, your provided no info on the oscilloscope. Even a real 1950 CRT scope will do better than that.If it is a legit scope, it might be defective or have a blown input. Check 50 ohm vs 1 meg impedance on the scope that might load up a cheap generator?Three, how is it connected (or badly connected) to the signal generator?

author: 807
author_rank: Frequent Contributor
timestamp: August 01, 2024, 10:21:38 am
content: A photo of the complete setup would be helpful too, showing the generator frequency setting & the scope display.

author: CaptDon
author_rank: Super Contributor
timestamp: August 01, 2024, 11:01:23 pm
content: Sweep rate set wrong and signal is aliased.

author: Shanza Baig
author_rank: Newbie
timestamp: August 09, 2024, 10:18:48 pm
content: Well, the horizontal scale does not matter because the auto button fits everything for you. The problem was the pulse width that i was applying. With that pulse width i was reaching the maximum limit of 1 MHz for the function generator so it was not able to apply higher frequencies. The oscilloscope was working perfect.
Frequency accuracy varies when I change Volts/Div on Hantek scope - Page 1
Forum section: electronics / beginners

author: Alanalan
author_rank: Newbie
timestamp: April 19, 2023, 02:20:28 pm
content: I am an intermediate beginner in electronics and brand new to digital scopes. I have the Hantek DSO5102PI noticed that when I hook the scope to the signal generator and pump in 10V at 1.7 KHz (sine wave) that the scope's onboard frequency counter loses accuracy when I lower the Volts/Div from 5v/div past 500mv/div . That is to say, that the last division the Hantek's onboard scope is accurate is at 500mv. When I go below that to 200mV, 100mV, 50mV, 20mV, and 10mV the frequency counter becomes way off.However, when I view the Hantek's measured frequency it is spot on.What gives?Addendum: I lowered the Voltage out from the function generator to 1V and raised the frequency to 1MHz. Now the onboard frequency counter works all the way down to 10mV/Div with absolutely no problem.What I don't understand is that the V/Div is only a "monitoring" function, yet when I change it it seems to affect the onboard frequency counter which, to my mind, should not be affected at all. Anyone know what's happening here ? I noticed the same effect on my analog scope as well.Alan

author: radiolistener
author_rank: Super Contributor
timestamp: April 19, 2023, 05:12:25 pm
content: Frequency is measured with hardware trigger, and trigger needs some min signal span, if you reduce vertical gain the trigger may not work when signal span goes below some limit. Usually it's about one grid cell on the display, but it may depends on oscilloscope type.When you increase vertical gain too much, it may lead to a false triggering due to noise. Also DC offset may prevent trigger to work, so you're needs to check if trigger level is at the center of signal.

author: Alanalan
author_rank: Newbie
timestamp: April 19, 2023, 07:18:32 pm
content: Thank you!That makes sense.
Frequency converter power calculation for synchronous motor start - Page 1
Forum section: electronics / beginners

author: alex.x
author_rank: Newbie
timestamp: April 02, 2025, 09:33:55 am
content: Hi guys!I am dimensioning a frequency converter for starting an AC synchronous motor.I have motor V, I locked, moment of inertia and break-away torque.I need to calculate the electrical apparent power S.So at the starting moment it should be $$S=V*I=T*\omega$$But since the angular velocity is 0 $$\omega=0$$ and the whole thing returns 0.Whats the catch? Where is the mistake?

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 02, 2025, 09:39:06 am
content: Is it not just locked current x voltage?

author: Benta
author_rank: Super Contributor
timestamp: April 02, 2025, 10:45:52 am
content: How is the motor started? Is is wired for asynchronous start with switch to synchronous operation close to lock in?Or does it have some other starting mechanism? Or will you start it by sweeping up the frequency?

author: alex.x
author_rank: Newbie
timestamp: April 02, 2025, 12:11:30 pm
content: Machine start is in syn mode.Also it is given that at the break-away torque of 7000 Nm is 30% of the rated system torque.How do I recalculate torque into VA and kW?.

author: alex.x
author_rank: Newbie
timestamp: April 02, 2025, 12:14:09 pm
content: torque and speed diagram
frequency counter "check" function? - Page 1
Forum section: electronics / beginners

author: xyzzy
author_rank: Contributor
timestamp: October 11, 2012, 05:11:40 pm
content: Greetings!I recently acquired a couple of used frequency counters (Tek CDC250, Fluke 1925A) without manuals. Both have a "check" function that's easily accessible enough that it seems like it must be something one would use often. Selecting "check" on either counter results in a display of 10 MHz. Obviously, this is the frequency of the internal oscillator.My question is as follows: what useful information is this feature intended to convey? If each counter only has one precision oscillator, how can it independently measure its own oscillator frequency? Is the counter hard-coded to simply display 10.000000 MHz, or is it actually measuring something?Thanks!

author: Fraser
author_rank: Super Contributor
timestamp: October 11, 2012, 05:15:39 pm
content: You are correct if you were interested in accuracy... a counter that checks itself without an external reference of known accuracy cannot tell you anything about its accuracy.BUT... the 'check' function is designed to test all the counter divider and processing chain for a 10MHz signal. It is a confidence check that the counter is actually functional. That is all.A word of caution here as well. Many high quality frequency counters incorporate a 'Pico' fuse inside the input socket or on the input board. This Pico fuse can fail due to an RF overload, yet the counter will still appear OK in its 'check' mode. I had this on an Advantest frequency counter. The seller thought the front end was blown when in fact it was just a simple Pico fuse that needed replacingRegardsFraser

author: xyzzy
author_rank: Contributor
timestamp: October 11, 2012, 05:26:20 pm
content: Quote from: Aurora on October 11, 2012, 05:15:39 pmThat makes sense. Thanks!

author: SeanB
author_rank: Super Contributor
timestamp: October 11, 2012, 06:00:39 pm
content: I remember those fuses, available from 50mA to 5A AFAIK.
Frequency-Dependent Transimpedance Amplifier Behaviour - Page 1
Forum section: electronics / beginners

author: The13thParish
author_rank: Contributor
timestamp: September 08, 2020, 12:38:37 am
content: Dear all,I am building a transimpedance amplifier for the purpose of converting a photocurrent from a silicon photodiode into a voltage which will then be fed into a microcontroller to actuate some further circuitry.My circuit is based on the very basic schematic attached from The Art of Electronics as a starting point. I am using an LF411 op amp and a wide-area silicon photodiode (5 mm x 5 mm) which I found in a box and for which I do not have a data sheet. The feedback resistor is 1 Megaohm and I amnotcurrently using a capacitor in parallel with Rfto dampen oscillations caused by photodiode parasitic capacitance.I can't seem to amplify a DC signal but I can amplify AC signals; that is to say, what I want is to take a constant light source in the visible region which gives rise to a DC current in the circuit, which then I can convert to a DC voltage. I could use an optical chopper to make the light an alternating source however in principle op amps should be able to convert and amplify a DC signal, so I want to improve my understanding.For troubleshooting purposes, it's easier by eye to find a 100 KHz AC-modulated signal on a scope rather than a DC offset from a background (i.e. room lights), so this is where I started. If I modulate the output of a white light LED using a function generator (sine used) as the LED voltage source, my circuit works at converting sinusoidal photocurrent to a sinusoidal voltage at the same frequency as the light. If I try using a constant light source I notice zero voltage conversion, as seen by zero difference from the oscilloscope baseline. Any tips?All the best,Ryan

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: September 08, 2020, 01:29:07 am
content: Hi,Can you show the supply connections to the LF411 opamp?What power supply rails are you using?Jay_Diddy_B

author: The13thParish
author_rank: Contributor
timestamp: September 08, 2020, 01:31:13 am
content: @Jay_Diddy_B,I am using +/- 15V directly connected to the op-amp power pins VCC+and VCC-respectively. I am not biasing the photodiode.All the best,Ryan

author: magic
author_rank: Super Contributor
timestamp: September 08, 2020, 05:30:52 am
content: Are you sure LED brightness is the same in both tests? What frequency did you test? Start turning it down and see what happens. Maybe you just hit a gain peaking sweet spot.Try 10MΩ perhaps. Do you know how large is the photovoltaic current supposed to be?
Frequency info help  - Page 1
Forum section: electronics / beginners

author: Gazmon
author_rank: Regular Contributor
timestamp: December 12, 2022, 05:34:15 pm
content: Hi,Looking at a square wave to sine converter circuit , my engineering maths is a bit rusty apologies ....I have the equation below , could anyone help me with the scientific calculation input plesse ?f = 1/(2π x R x C)Values can be as an exampleAppreciatedGary

author: wasedadoc
author_rank: Super Contributor
timestamp: December 12, 2022, 05:46:21 pm
content: That equation gives the frequency at which the output of a RC low pass filter is 3dB lower than the input. (Series R, then C in parallel with output)For example R=10k, C=10nF. f=1.592kHzA single RC filter will not give a true sine wave from a square wave as it does not completely eliminate all the harmonics of the fundamental frequency of the square wave.

author: Zero999
author_rank: Super Contributor
timestamp: December 12, 2022, 07:39:04 pm
content: Several filters in series will do a reasonable enough job of cutting the harmonics enough to produce a decent sine wave.

author: rstofer
author_rank: Super Contributor
timestamp: December 12, 2022, 07:51:59 pm
content: https://www.nutsvolts.com/magazine/article/making_wavesA 4 stage filter can do a pretty decent job but the output is considerably reduced relative to the input.
Frequency inverter - 1 phase - Page 1
Forum section: electronics / beginners

author: cs.dk
author_rank: Unknown
timestamp: September 21, 2012, 06:20:22 am
content: Hi,Is it impossible to run a 1-phase 240V motor with a frequency inverter? All 1-phase inverters i've seen is fed with 1 phase, and outputs 3x240V. Why is that?I've got a 3-phase Omron Varispeed V7 on my relative large drill press. But would like to control my little 1-phase drill press the same way.Any ideas?

author: IanB
author_rank: Super Contributor
timestamp: September 21, 2012, 07:06:47 am
content: For one idea, see this video and jump to 2m20s:It's an induction motor speed controller project from Silicon Chip magazine. It will control both single phase and three phase motors.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: September 21, 2012, 12:17:46 pm
content: QuoteNo, it is not possible.QuoteBecause you can drive a 3-phase motor from a single phase power outlet.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 21, 2012, 05:31:34 pm
content: When I search google for "single phase variable frequency" the second hit is leads to:http://www.anaconsystems.com/text/opti_e2.htmlAnyway, yes it is possible to run a single phase motor from a variable frequency inverter. It is not common because 3 phase motors are better -- uniform torque, less vibration, more efficient, and less complicated (no startup winding/capacitor). Single phase motors are common because three phase power is not always available, may be wired incorrectly, and causes problems if you lose one phase. If you are going to use an inverter anyway you might as well make it output three phase and use a three phase motor.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: September 21, 2012, 06:39:02 pm
content: QuoteYes, with special one, as linked.But these are very expensive. Hence I would also recommend to buy a 3 phase motor (e.g. a used from ebay) to replace the 1 phase motor. Since you can only work on one machine at the time, you could switch either the one or the other machine to the inverter.I said it is not possible regarding to cs.dk´s initial question to use its existing 3phase inverter.

author: cs.dk
author_rank: Unknown
timestamp: September 22, 2012, 09:48:47 am
content: Thanks for the answersThe motor speed controller will cause loss of torque at low rpm's i think?Well 365$ for a inverter drive isn't that expensive. Have to order one.

author: IanB
author_rank: Super Contributor
timestamp: September 24, 2012, 12:34:06 am
content: Quote from: cs.dk on September 22, 2012, 09:48:47 amI'm not sure. Probably depends on the design of the motor. If the motor was not designed for a variable speed drive, then it will probably only deliver optimal performance at the design speed.
frequency limiter fault - Page 1
Forum section: electronics / beginners

author: charon1985
author_rank: Contributor
timestamp: May 01, 2017, 05:28:47 am
content: Hi, i need a schematic or and idea how to make a circuit that will react if the frequency of the input signal is below a certain value. I have a motor that runs up to 40 000 rpm, it has a hall sensor that outputs a square signal 50% on 50% off only the frequency varies... if the motor is under high load the rpm will decrease. I want to have a circuit that will monitor the frequency and output an error signal if the frequency is under a set value. I have searched on internet but did not find anything. The problem is that i dont know what to search for.I would prefer not to use uC.Thank you.

author: ebclr
author_rank: Super Contributor
timestamp: May 01, 2017, 05:43:18 am
content: With thishttp://www.bittnar.info/en/tachometer-rcexl-alternative-firmware/And a very simple trick on firmware you can make what you want

author: charon1985
author_rank: Contributor
timestamp: May 01, 2017, 05:54:47 am
content: I forgot to mention that i need a reaction speed of 2-3 cycles from the given frequency.

author: ebclr
author_rank: Super Contributor
timestamp: May 01, 2017, 06:43:46 am
content: CD 40106 and a bunch of diodes / resistor / capacitor will do what you want

author: Ian.M
author_rank: Super Contributor
timestamp: May 01, 2017, 06:50:19 am
content: Use a retriggerable monostable to stretch the tacho signal to the point that it stays high continuously if its above the limiting speed. Use the same tacho signal to clock the monostable output into a D type flipflop so that you get a continuous level updated once per tacho signal cycle rather than a narrow low going pulse .

author: Assafl
author_rank: Frequent Contributor
timestamp: May 01, 2017, 07:04:09 am
content: I know you said no uC but nowadays I'd probably use an ATTiny on a breakout board (e.g. like an Adafruit Trinket). It is far too easy to use - to not use oneThe timers on it and hardware interrupt handler make it especially useful for this TINY circuit.... With the Arduino bootloader it could really be 10-15 lines of code or so... (use attachInterrupt on the input pin; the interrupt handler sets a volatile variable to millis(); and the main loop just compares the current millis() to the previously stored millis() - if it is too long - the output goes low... ).It is probably cheaper too....Were it 1990's again, I'd probably use a CMOS counter like a 4060 driven by a xtal and some jumpers (or DIP switch) to set where the minimum rate was (obviously the hall effect sensor would reset the counter every rotational cycle and the purpose would to NOT allow the counter to reach a certain value which would trigger an error latch). Would obviously need an AND gate or diodes to sense when the count was up.Obviously the same circuit with a variable frequency source would be simpler, with the latch connected to one of the bit outputs. But also less "programmable" and accurate in nature.
Frequency rating on SMD resistors - Page 1
Forum section: electronics / beginners

author: geggi1
author_rank: Frequent Contributor
timestamp: February 11, 2015, 10:20:07 pm
content: Is there any frequency rating for SMD resistors.I'm playing with some AD8307 Log amps to make RF field strength meter/ power meter.On the meter I'm using 2 100 ohm resistors in paralell to convert the input impedance form 1,1K to 50 ohm.In the future I'm planning to use AD8313 to make a meter up to about 2,5Ghz.

author: retrolefty
author_rank: Super Contributor
timestamp: February 11, 2015, 10:37:25 pm
content: Should be fine. It's wirewound resistors that you have to look out for when terminating RF frequencies as the extra inductance will cause error. I too build a RF milliwatt meter using a AD8307, great chip for up to 500 Mhz or so. Are they still around $15 a pop?Going up to >2gHz will be a challenge where PCB material and traces will effect accuracy as much as the active and passive components.

author: babysitter
author_rank: Frequent Contributor
timestamp: February 12, 2015, 05:15:18 am
content: Sounds like a no-brainer, but datasheets might contain impedance over frequency plots.Without datasheet it is preferrable to use the smallest SMD resistors you can handle. To parallel, for example 2x100 Ohm to get 50 Ohm, which I did recently for a resistive divider, I stacked 2 SMD resistors on top of each other to keep the Trace at the right microstrippy size.

author: rfbroadband
author_rank: Unknown
timestamp: February 16, 2015, 10:47:55 pm
content: if you go through the math (equivalent circuit of an SMD resistor) you will find that each size has an resistance value where the impedance remains mainly constant over frequency (thus neither inductive nor capacitive behavior). For 0402 this turns out to be ~ 100Ohm, thus using 2 100 Ohm in parallel to create a broadband 50 will work nicely beyond 10GHz. below that ZOpt the R is inductive, above ZOpt it capacitive. For 0603 sized SMD R ZOpt is higher than 100 Ohm, even more so for 0805.I hope this helps.
Frequency Response of a sensor - Page 1
Forum section: electronics / beginners

author: Nick_Kimi
author_rank: Newbie
timestamp: January 05, 2016, 05:26:24 pm
content: Hi there,I would like to measure the frequency response of a radio frequency current transformer (as attached) using DSA815 1.5 GHz Spectrum Analyzer. How can I do that? I try a few times, and this is what I got (as attached) and I dont think it represent the frequency response of the sensor.Many apologies for any inconvenience caused.
Frequency response of passive return-to-zero downconversion mixer - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: July 07, 2018, 11:07:44 am
content: Why for fourier analysis/representation of square wave, the book snippet shows first harmonics to have amplitude of 2/pi ?https://en.wikipedia.org/wiki/Square_wave#Fourier_analysisQuoteCould anyone elaborate on the above book sentence quote ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 07, 2018, 06:35:42 pm
content: Amplitudes are peak, not RMS. Not that that matters regarding the factor of pi, for which that's simply the amount needed to reconstruct a square wave.Tim
Frequency response of zener shunt regulator - Page 1
Forum section: electronics / beginners

author: cellularmitosis
author_rank: Unknown
timestamp: October 02, 2020, 08:20:29 pm
content: Hey guys, just wanted to sanity-check that I'm using LTspice correctly.I wanted to see what the frequency response of a basic zener diode shunt regulator looked like (see screenshot 1).I was surprised that the drop off was only about 4db, then plateaued? This can't be right -- a zener only loses 4db of regulation out to 10GHz?I looked through the On-Semi "Zener Theory and Design Considerations:https://www.onsemi.com/pub/Collateral/HBD854-D.PDFThey seem to indicate a simple 1/2 watt low voltage zener's capacitance would be under 1000pF, so I placed a capacitor in parallel and simulated that as well (see screenshot 2). This produced a more expected result -- there is a rolloff which doesn't stop at just 4db.This second simulation seems to indicate a basic shunt regulator should still be in regulation out to 100MHz. Is this realistic?

author: srb1954
author_rank: Super Contributor
timestamp: October 03, 2020, 12:13:56 am
content: Quote from: cellularmitosis on October 02, 2020, 08:20:29 pmIt is probably the bulk series resistance of the Zener crystal that limits the maximum amount of HF attenuation available.Up to 100kHz the attenuation is governed by the dynamic DC resistance of the Zener. Above 100kHz the impedance of the Zener junction capacitance starts to take effect and provides further attenuation. However, around the 10MHz mark the impedance junction capacitance drops below the bulk resistance of the Zener and is unable to further reduce the attenuation, hence the plateau.You could get a similar effect with your second simulation with the paralleled capacitor by increasing the ESR of the capacitor considerably. You should then see the same plateau effect in the attenuation.
Frequency standards, GPS V Rubidium, and noise question - Page 1
Forum section: electronics / beginners

author: Chris Wilson
author_rank: Super Contributor
timestamp: June 02, 2012, 06:46:18 pm
content: I am looking to get a frequency standard for my amateur radio shack, initially for verifying test gear readings, but later as a standard to lock receiver oscillators to. I was going to buy a GPS frequency standard but a friend warned me these have noise issues when I come to use it with an oscillator in RX / TX applications. It's not something I had considered, so what's the score here please? Should I not buy a GPS standard? Thanks. Any links to known safe purchase sources from personal experience welcome, either here or by PM or e-mail.

author: Bored@Work
author_rank: Super Contributor
timestamp: June 02, 2012, 07:03:25 pm
content: There is a mailing list, called time-nuts somewhere on the Internet. The people there usually know such details.

author: Chris Wilson
author_rank: Super Contributor
timestamp: June 03, 2012, 03:47:54 pm
content: Thanks Bored@Work, found it, joined it and received some great replies from obviously specialist folk. Cheers!
Frequency to Voltage Convertor - Page 1
Forum section: electronics / beginners

author: ccrunner84
author_rank: Newbie
timestamp: May 19, 2014, 06:13:54 pm
content: I'm trying to log ethanol content using a flex fuel sensor, however it doesn't provide a 0-5V DC signal but it does provide an output frequency. I've googled and found that this is possible but I don't know where to even begin after reading a few threads.Are there calculators out there? I'm trying to convert say 50–150?Hz into 0-5VDC.Thanks

author: FrankenPC
author_rank: Unknown
timestamp: May 19, 2014, 06:15:51 pm
content: Use a small microcontroller? Read the pulse in and convert to 5V with a DAC out??

author: fcb
author_rank: Super Contributor
timestamp: May 19, 2014, 06:23:32 pm
content: LM2907 (National now TI part).F>V converter IC.

author: leppie
author_rank: Frequent Contributor
timestamp: May 19, 2014, 06:30:15 pm
content: Counting pulses is surely easier and more accurate than converting it to a voltage and then reading it with an ADC (at least in terms of a microcontroller).

author: fcb
author_rank: Super Contributor
timestamp: May 20, 2014, 10:29:20 am
content: I agree counting pulses would more straight forward if the OP wants to design the whole logger from scratch. It's quite possible they just want to use a COTS logger though.The LM2907 can be at least 0.5% accurate, so probably good enough for their application.

author: electronics man
author_rank: Frequent Contributor
timestamp: May 20, 2014, 10:45:51 am
content: How about thishttp://www.rapidonline.com/electronic-components/lm2917n8-frequency-to-voltage-converter-34504

author: ccrunner84
author_rank: Newbie
timestamp: May 20, 2014, 01:22:56 pm
content: Thanks for the replies, I'll look at some of these links later today. I'm not looking to design a logging device, just need a 5V signal to provide to one.

author: David Hess
author_rank: Super Contributor
timestamp: May 20, 2014, 05:33:38 pm
content: Counting the frequency is almost always a better solution but there are several ways to do frequency to voltage conversion. The easiest are to either gate a current source or charge into an RC filter. The precision way is to use the input voltage of a phase locked voltage to frequency converter.
Frequent sd card corruption RPi2 - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: June 27, 2015, 08:05:21 am
content: 1. I am using RPi2 model B with raspbian loaded.2. I usually shut down completely RPi2 board, before taking off the power.3. But still I see frequent SD card corrutption.4. SD card is also from Sandisk only-8GB.5. When I power up board it just got stuck on first screen & never gets started.6. There is no power error on board as there has been no rainbow box on top right of screen.7. After this if I reload the image on SD card & run then it start working again.
Fresenius conductivity sensor pin configuration - Page 1
Forum section: electronics / beginners

author: alnstn10
author_rank: Contributor
timestamp: July 14, 2022, 03:39:21 am
content: I was expected to use the Fresenius hemodialysis series bibag conductivity sensor to measure the conductivity of water, but I didn't find any reference about using this sensor.In the test, the sensor is connected to the Analog Device EVAL-CN0359-EB1Z as a display of the conductivity. I've tried various pin configurations, but I'm still not sure because the conductivity results obtained from both are very different from testing using a probe-type conductivity sensor.What is the correct pin configuration of the sensor?

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: July 14, 2022, 12:54:42 pm
content: I can ask the tech at dialysis on friday.He might know but if not might have a schematic of the machines circuit.Jeff

author: alnstn10
author_rank: Contributor
timestamp: July 15, 2022, 08:22:57 am
content: Hi Jeff,That would really help me, thank you very much.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: July 16, 2022, 12:15:41 am
content: He was only there for a very short time today and I did not get a chance to ask.My next day is monday. Sorry, now I am interested too.Jeff

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: July 19, 2022, 12:55:52 am
content: I got to talk to him today. He will research it and get back to me.Our machines do not use the bibag but they could be attached as an option.They are dual sensors not just one in each and thats about all so far.Jeff

author: alnstn10
author_rank: Contributor
timestamp: July 19, 2022, 01:43:57 am
content: oh yeah, it seems possible in 1 sensor there is a temperature and conductivity sensor

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: July 20, 2022, 11:32:56 pm
content: No luck they consider this IT protected tech and he does not want to be fired.What I was told is that the information is on line so can be found.The sensor is dual conductivity no temp sensor because temp is controlled asis material added to the water so these are for measurements in a finite area.The calibration is done with other test equipment seperately so these sensorsonly measure a small range in a controled enviroment.Jeff
Fresh from Raw C on AVR - Page 1
Forum section: electronics / beginners

author: Hatsune_electronic
author_rank: Newbie
timestamp: July 05, 2024, 06:29:15 pm
content: HelloI was recently gifted a STM32401ccu6 dev board(black pill to be acc.)And i know how to program AVR chips in C(mostly)How do i begin using the STM32These are kinda hardi have the IDEAny advices are welcom

author: pcprogrammer
author_rank: Super Contributor
timestamp: July 05, 2024, 06:39:27 pm
content: Hi, and welcome on the forum.Moving from "raw" C on AVR to STM32 ARM is not that difficult, if your "raw" means bare metal.When familiar with register programming on peripherals in the AVR you most likely also know how to interpret the reference manual.So get yourself thereference manualanddata sheetof the STM32F401, and start reading.First thing to get right on the STM32 is the clock setup and the enabling of the peripherals. This is different to the AVR setup. Once you did this once using the chip is not hard to learn.See my github repositories for how it is done on some of the other STM32 chips, like for instance theF303. The principle is basically the same on the F401.Another option is to use the Arduino environment that most likely has support for the F401 boards.Edit: I forgot to mention that you can use any IDE that allows compiling with the GNU arm compiler. No need for the STM Cube IDE. Even a simple text editor with command line instructions to run a makefile can get you up and running.Also very easy is to use the ST-link V2 (clones) to upload the code and even debug it. Lots of examples on how to do this are to be found on the net.
Fried Transistor... - Page 1
Forum section: electronics / beginners

author: JacobEdward
author_rank: Regular Contributor
timestamp: March 07, 2015, 11:09:54 pm
content: This is the datasheethttps://www.fairchildsemi.com/datasheets/2n/2n3906.pdfThe maximum voltage rating for the collector is suppose to be 40V and it fried from a 17V source... also the switch completely broke down... am I reading this right? You control the transistor with a 5V signal and the collector/emittor at most 40V? I've attached a screen shot of the specific part of the data sheet I'm reading

author: xrunner
author_rank: Super Contributor
timestamp: March 07, 2015, 11:19:48 pm
content: Well, you say "control it with a 5V signal" but you really turn it on with a smallcurrent. It can come from a 5V supply, but you need a resistor to drop a lot of that voltage so the transistor turns on with a small current. It may have pulled too much current even if it was connected to a 17V supply - need more details of the circuit ...

author: Seekonk
author_rank: Super Contributor
timestamp: March 07, 2015, 11:37:47 pm
content: If you drove something inductive like a relay, more than 40V can be generated. The transistor figured out exactly what it was supposed to do, short out. Post a circuit and we will figure where things went wrong.

author: sleemanj
author_rank: Super Contributor
timestamp: March 07, 2015, 11:51:47 pm
content: The 3906 is a PNP transistor.The Collector to Emitter junction as a breakdown of negative 40v in the off condition, that is for example the collector at 40v and the emitter at 0v, or the emitter at 17v and the connector at 57v, etc..The 40v is telling you just how much "reverse" voltage across the transistor it can stop, just like a diode'sreversebreakdown voltage.The Base to Emitter junction can withstand 5v, in the off condition that is, the base can be 5v and the emitter can be 0v (or 10v and 5v, or ....). Remember this is a PNP, if the BASE is (close, equal or) higher than the Emitter then the transistor is OFF. Remember the emitter to base is effectively a diode, this is telling you that this diode can withstand up to 5v reverse biasing. In other words 5v figure is telling you, in a way, just how "hard" you can "push" it into the off region.Remember it's a PNP, you "pull" the base down lower than the emitter (by way of an appropriate current selection, this is a BJT not a FET), to turn on, and "push" it up to the emitter to turn it off.Post your circuit diagram.

author: Zero999
author_rank: Super Contributor
timestamp: March 08, 2015, 12:09:33 am
content: A schematic would help.There are plenty of ways to blow up a transistor, other than overvoltage.
fritzing - Page 1
Forum section: electronics / beginners

author: snipersquad100
author_rank: Frequent Contributor
timestamp: February 20, 2013, 04:21:49 pm
content: Hi what do you guys think ofwww.fritzing.org

author: firewalker
author_rank: Super Contributor
timestamp: February 20, 2013, 04:29:19 pm
content: Heave a look to the threads bellow.https://www.eevblog.com/forum/eda/fritzing/https://www.eevblog.com/forum/open-source-kicad-geda/open-source-fritzing-pcb-software/Alexander.

author: ivan747
author_rank: Super Contributor
timestamp: February 20, 2013, 04:34:59 pm
content: It is not a competitive CAD tool, and its simplicity doesn's make for its limitations.If you are looking for a very simple CAD tool take a look at Livewire/PCB Wizard, but don't expect to use it for long.I predict you will eventually move to Eagle or Diptrace.

author: snipersquad100
author_rank: Frequent Contributor
timestamp: February 20, 2013, 04:47:24 pm
content: thank you for you input
Friwo Power Supply Repar - Page 1
Forum section: electronics / beginners

author: jerryk
author_rank: Regular Contributor
timestamp: January 08, 2019, 09:50:10 pm
content: I have a Friwo power supply that died during an earthquake event. We lost power for a long period of time but my guess is there was a significant surge that is related to cause of death.I'm trying to identify R27 for starters since it is obviously faulty. My best guess is it starts with a 1 and has 4 digits. I understand the numbering system but assume that the R value is important. Any guesses on what it's value might be.Any thoughts on repairing this thing would be appreciated since they are proud these things since they charge a satellite phone.Thanks -Jerry
From a framebuffer to HDMI, any off the shelf solutions? - Page 1
Forum section: electronics / beginners

author: Mechanical Menace
author_rank: Super Contributor
timestamp: May 12, 2015, 06:21:15 pm
content: I've been playing with an FPGA to take the contents of a framebuffer and transmit it as HDMI, but I'm pretty certain I'll never manage get my Spartan 6 to run fast enough to output 1080p, tbh I'd be surprised if I manage 720p at 30 fps. Does anyone know of any products that can already do this?Thanks.

author: miguelvp
author_rank: Super Contributor
timestamp: May 13, 2015, 12:30:53 am
content: Forum member hamster_nz was able to drive and an HDMI signal at 1080p it even without an HDMI TX chip:http://hamsterworks.co.nz/mediawiki/index.php/Spartan_6_1080pAnd he was featured on hackaday for it:http://hackaday.com/2013/03/08/pumping-1080p-video-out-of-an-fpga/Not sure hamster's implementation would work at full resolution with a frame buffer involved but he is full of surprises so maybe it's possibleBut I think with an ADV7513 or similar HDMI-TX with a good DMA implementation it should be easier.http://www.analog.com/en/products/audio-video/analoghdmidvi-interfaces/analog-hdmidvi-display-interfaces/adv7513.html#product-documentationYou can look at this app note with some verilog examples related to the ADV751x family:http://www.analog.com/media/en/technical-documentation/application-notes/AN-1270.pdfThere are other HDMI-TX chips, so maybe a search for "Xilinx Spartan 6 HDMI-TX example" might find you more information.Also note that those chips also support audio.

author: hamster_nz
author_rank: Super Contributor
timestamp: May 13, 2015, 07:44:45 am
content: I recently learnt the secret of 1080i, and that too is achievable from a Spartan 6. It isn't well documented how you do it.If you want a hand in any way just drop me an email ..

author: bruce273
author_rank: Contributor
timestamp: May 14, 2015, 02:58:39 am
content: I'm unsure if you can buy the chips that graphics cards use, I can't remember the name of them but basically the gpu is doing the heavy lifting in respect to the 3d work but the result is passed to a frame buffer. I believe all GPUs must have a frame buffer mapped to a standard location of memory on the computer in order to allow the post messages and other things to be rendered before the OS loads the driver. There's some examples with the raspberry pi into how to access the buffer and pull some information. Though actually writing a program to display a framebuffer using the pi's hdmi port would be a fair challange I would think.http://raspberrycompote.blogspot.co.uk/2012/12/low-level-graphics-on-raspberry-pi-part_9509.html
From where to source out-of-stock ICs - Page 1
Forum section: electronics / beginners

author: rkosegi
author_rank: Newbie
timestamp: March 05, 2022, 07:22:07 am
content: I'm struggling for some time to find LTC2309 (TSSOP-20) in any of online shops. It's just out-of-stock.Since I'm fine to salvage it from some junk product, can someone suggest something? or in more general sense, is there something like reverse BOM search where I can put part that I'm interested in and it will give me products that this part was used in?Thanks

author: Kleinstein
author_rank: Super Contributor
timestamp: March 05, 2022, 09:37:24 am
content: I don't konw a good way to search for products that us a certain chip. A general search enging and look for the part and repair or spare may be small chance.Another option may be to find a compatible part - it may or may not exist and than there is a chance it is also not in stock.

author: Terry Bites
author_rank: Super Contributor
timestamp: March 05, 2022, 06:34:00 pm
content: Try and scrounge a sample from AD.
Frying bacon sound when shorting power supply? - Page 1
Forum section: electronics / beginners

author: help_me_pick_username
author_rank: Contributor
timestamp: November 11, 2019, 08:16:14 am
content: I bought a Gophert CPS3205 power supply. When I short the two output terminals, there is a frying bacon sound coming from the PSU. When I use the connection wires they provided, which were pretty crap since they have a pretty high resistance, the frying sound goes away completely. It's only when I use proper wires.Since the PSU has current limiting, I was wondering if maybe this sound is happening because the PSU is delivering that current at a very low voltage (5A at only 0.3v when properly shorting(bacon sound), 5A at 6.5v with included low-quality wires(no bacon sound)). Also, the pitch and 'sizzling' of the bacon sound changes as I change the current limit. Could this be why? If so, why does the sound occur?If not, what could be a likely cause of this sound? ...also, It's not bad to short the PSU, right? Since it has Short Circuit and Overcurrent Protection?

author: xavier60
author_rank: Super Contributor
timestamp: November 11, 2019, 09:04:34 am
content: One of my bench supplies makes a faint hissing or rattling sound under the same conditions because its SG3525 control IC isn't able to reduce the MOSFET's drive pulse width below a certain amount, so randomly skips pulses to get the average duty cycle low enough.It's this random pulse skipping that causes audible noise from the magnetics.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 11, 2019, 10:15:51 pm
content: Just generally -- I wouldn't recommend operating at full load current at low voltages. The switching losses in those stupid things can be fatal. At low voltages, the switching duty cycle is very low, so that it's basically all switching, and the efficiency is atrocious.Once had a one of those 100V 10A supplies nuke itself in this way. They used 50A IGBTs for switching -- terribly oversized for the supply's ratings (overcompensating for their poor design, perhaps?), big gate capacitance. Yet driven with mere 2SC1815s, far too weak. Switching speed was about a microsecond...If the circuit is actually well designed, it should be fine at all conditions. And yeah, the hiss should just be the control loop struggling with timing limitations at this extreme operating condition -- that's not unusual and not necessarily fatal. And if it's not well designed, it can possibly be improved, but that will require much inspection (and at which point, you might as well buy a good name brand..?).Tim

author: Zero999
author_rank: Super Contributor
timestamp: November 11, 2019, 10:39:14 pm
content: Yes, the control circuit is struggling with the extremely low duty cycle and high peak currents. The power supply is not designed to be continuously operated with the output shorted. The current limit is there to protect it from damage, rather than a normal operational mode.
FSIG3: Help to find operation manual - Page 1
Forum section: electronics / beginners

author: zulunation
author_rank: Contributor
timestamp: January 15, 2021, 09:53:54 pm
content: Hi everyone,I am searching any documentation on the FSIG3 spectrum analyzer.The only document i found was that:https://accusrc.com/uploads/datasheets/7874_FSIG.pdfI would like to get any operation manual or any other documentation.Function description, menu description.Any document's which R&S gives to it's customers.Thanks,

author: Terry Bites
author_rank: Super Contributor
timestamp: January 16, 2021, 01:21:10 pm
content: https://www.rohde-schwarz.com/my/manual/search-for-manuals-general_251441.html?term=*&sort=relevanceTry emailing R&S service@rohde-schwarz.com ?

author: zulunation
author_rank: Contributor
timestamp: January 16, 2021, 03:40:07 pm
content: Thanks for reply.Already sent email to R&S. Two weeks ago.A support guy told that this document is not available in their current archives so they will try to find it in R&S museum.Still waiting.
FSR or non-tactile membrane switch - Page 1
Forum section: electronics / beginners

author: jamessexycarrot
author_rank: Newbie
timestamp: September 22, 2022, 11:48:51 pm
content: I bought one of these for an Arduino project and was convinced that this is a 'a series of non-tactile membrane switches' but then after messaging the 3rd party seller, he told me it was 'thin-film contact sensors'.I then searched for "thin-film contact sensors' and found out its simply another word for "Force Sensing Resistors" or "tactile pressure sensor" or "tactile force resistor"Am I right, is he's right, are we're both talking about the same thing and are confused about synonyms , or is neither of us is right?James

author: rooppoorali
author_rank: Regular Contributor
timestamp: September 23, 2022, 03:28:20 pm
content: I think the seller is right. Usually, matrix keypads are called membrane switches. It does not look like FSRs either.

author: eugene
author_rank: Frequent Contributor
timestamp: September 23, 2022, 03:47:04 pm
content: What signal is produced?