hybridfree/eevblog-posts huggingface dataset:
Peiker TM810 NOT working. Need help fixing it. - Page 1
Forum section: electronics / beginners

author: Denislav Mitov
author_rank: Newbie
timestamp: May 29, 2020, 04:15:34 pm
content: HelloMy name is Denis and I work as a firefighter here in Bulgaria. I have a problem with the mirophone in the rescue basket of a firefighting ladder. The microphone is Peiker TM810. Last month it stopped working and I decided to see what is going on. I disassembled it and saw that one of the wires (the white wire) coming out of the microphone coil was crushed. Must have happened during manufacture because it was not disassembled from us before. However I carefully soldered the wire and the microphone was working. Until yesterday when someone told me it stopped working again. Today I disassembled it again and there were no wires crushed or detached. I checked the cable and it showed that it was shorted somewhere. Changed the wire measured it and it showed 27V. That is my first question is it normal to have voltage on the output cable? I also probed some resistors and a 2k2 one measured 0. Changed it, soldered the wires, measured voltage and it showed 9.9 V. Second question if it is normal to have the 27V on the cable shouldn't it stay 27V? I have attached 2 pictures of the front and the back of the PCB in the microphone. Thank you.
Pen-and-paper experiment. - Page 1
Forum section: electronics / beginners

author: hamster_nz
author_rank: Super Contributor
timestamp: May 25, 2020, 12:10:31 am
content: I was just played around with a pen and paper, and did something that others might find interesting to do.- calculate the power from 0.5V DC into a load (say 1 ohm)- calculate the power from 0.5V 1Hz square wave (that is +0.5V / -0.5V with 50% duty cycle) into the same loadAdd the two signals together (giving a square wave with a DC offset, that alternates between 1V and 0V)- calculate the average voltage of this signal- calculate the average power of this signal- work out the equivalent DC signal that delivers the same power to the same load- work out the equivalent square wave AC signal that delivers the same power to the same loadFor me, it really has the feeling of "oh, that is just blindingly obvious", and "wait, what what? how does that work?" and "So where, if anywhere, does the extra 0.207V DC come from". For me the math is simple, but (at least for me) the implications are very interesting.Then play around with a few other combinations, maybe changing duty cycles, or maybe graphing the adding of square waves of different frequencies, and perhaps the most interesting the same frequency but with different relative phases (e.g 90 or 180 degrees, pi/2 or pi if you like radians).

author: bob91343
author_rank: Super Contributor
timestamp: May 25, 2020, 01:21:35 am
content: All good stuff, learning the simpler math of Ohm's law.

author: jeroen79
author_rank: Frequent Contributor
timestamp: May 25, 2020, 01:59:19 am
content: The voltage is squared not only in the waveform.

author: hamster_nz
author_rank: Super Contributor
timestamp: May 26, 2020, 09:56:21 am
content: So DC + one square wave is relatively easy.I can simple add the power of a 1Hz and 2Hz square wave into a standard load and get the correct answer for the total powerWhy then can I not simply add the power of a 1Hz and 3Hz square wave and get the correct answer for total power?For example:1V AC square wave at 1 Hz into a 1 Ohm load is 1 Watt.1V AC square wave at 3 Hz into a 1 Ohm load is 1 Watt.But (1V AC square wave at 1Hz added to a 1V AC square wave at 3 Hz) into a 1 Ohm load isn't simply 2W.(yes, I have an answer to why... but just to show that it isn't always super simple)
Penta Power - Page 1
Forum section: electronics / beginners

author: david69
author_rank: Regular Contributor
timestamp: March 15, 2014, 02:59:03 pm
content: Hi, Can I look for somewhere datasheets for these components? A69154, A71003, A71011?They are from Penta Power DC motor driver? Thank Youfor any idea. David

author: facumedica
author_rank: Contributor
timestamp: March 15, 2014, 03:12:45 pm
content: If you didin't find them on Google, they are maybe some kind of custom ICs.

author: david69
author_rank: Regular Contributor
timestamp: March 20, 2014, 04:25:05 pm
content: I found working isolated SCR, NPN transistor and UJT transistor :-) good, working
perfboard - Page 1
Forum section: electronics / beginners

author: ethhanners
author_rank: Contributor
timestamp: February 13, 2014, 10:38:12 pm
content: so I am faily new to electronics and I find it very annoying to use perfboard I layout the commponents then solder but when I try to figure out what component leads need to be connected it is annoyingly difficult I have tried using sharpie to mark the leads but it didn't work well

author: mariush
author_rank: Super Contributor
timestamp: February 13, 2014, 10:56:10 pm
content: If you have a printer, you can draw the layout of the pins in Paint or some software (Fritzing for example) and then flip the picture horizontally and print it (or just leave it displayed on the screen) and you then basically have the pins as they show up on the other side of the pcb. Now you have a quick guide to tell you what pins gets wires to what pin.

author: ethhanners
author_rank: Contributor
timestamp: February 14, 2014, 01:33:15 am
content: thanks!!!

author: JoeO
author_rank: Frequent Contributor
timestamp: February 14, 2014, 01:50:24 am
content: Quote from: ethhanners on February 14, 2014, 01:33:15 amEdit your profile to identify the country you are in. That will really help.
Perf board practice. - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: January 28, 2018, 11:28:53 am
content: Please excuse the pride post, but I've been trying to practice my perfboard skills.It's just an ATMega328p minimal board.... and it's ugly bits ...Features:* Red 5mA power LED* Blue 5mA test LED on PIN (IDE) D9* 5 pin serial programming header* Reset switch w/ 10K pull up* 16Mhz xtal with 22pF load caps* 100nF decoupling capThe epiphany was using component leads, either from the ones you are using in the circuit or some cheap blue chinese resistors cut up to make the tracks on the underside. At the very last minute I cooked the power LED somehow. Ended up having to drill the holes back out to remove it, but I managed to get a new one in and nobody would even notice. It's always the last bit that goes tits up. Also... why is it that the best solder joint you make is the one you weren't meant to?There is another phase to this as I want to add the ISP header on the other side of the chip. I'm calling the AVR designers some interesting names for crossing power pins and the ARef pin polarity as I "could" have just linked across under the chip, but they are crossed, so I will need at least one insulated link on the underside.It's a practice precursor to my next perfboard project which will be a binary clock. It will be a bit of a step up as it entails:* an ATMega328p* 2x 74HC595 shift registers (mins and secs)* RTC chip* Battery backup* 16 LEDs* 16 Resistors

author: paulca
author_rank: Super Contributor
timestamp: January 28, 2018, 11:36:11 am
content: This is the schematic it's based off:

author: Nusa
author_rank: Super Contributor
timestamp: January 28, 2018, 12:31:46 pm
content: If it works, it's a win!Don't forget you have two sides to the board if you need to make crossovers with bare wire.Get yourself a roll of wire wrap wire (more if you want multiple colors). It's great for prototyping.

author: German_EE
author_rank: Super Contributor
timestamp: January 28, 2018, 01:10:22 pm
content: Looks good, and there's nothing wrong with connecting up perfboard like this for low voltage work.

author: Wimberleytech
author_rank: Super Contributor
timestamp: January 28, 2018, 02:14:24 pm
content: Nice work. You are very patient. I discovered DIY PCBs about a year ago and have not gone back to hand wiring.

author: paulca
author_rank: Super Contributor
timestamp: January 28, 2018, 04:37:39 pm
content: Quote from: Wimberleytech on January 28, 2018, 02:14:24 pmThere were times. Muttered expletives and it did nearly get chucked across the room at least once. Usually when I burnt myself trying to hold a pin I was soldering the other end of and it wouldn't take.DIY PCB... as in acid etched or do you mean order from a PCB house in China?I'm tempted to start looking into PCB CAD, it's definitely on the list for when I get round to it. The binary clock project might need some careful layout sessions, where a PCB layout editor might help, rather than just winging it and getting lucky as I have been doing.
Perf board track wire - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: January 31, 2018, 01:46:09 pm
content: Would this stuff work for making tracks on perf board?I would assume something like 0.315mm / 9amp would be convenient for most things?https://www.ebay.co.uk/itm/TINNED-COPPER-FUSE-WIRE-FULL-RANGE-50grams/112028568439

author: Buriedcode
author_rank: Super Contributor
timestamp: January 31, 2018, 02:28:52 pm
content: I'm never sure what people mean by 'perf board' anymore, since originally it was just perforated board - no copper pads or tracks. These days it can either mean, one pad-per-hole or strip board/vero board.Either way, if you are talking about tracks at the bottom, then yes I'm sure it will be fine. This also works for 'jumpers' on the component side (of stripboard), although I tend to use cut-offs for those, like the left over legs from resistors and caps.Generally, I tend to buy 1/0.6mm hook-up wire, and strip the insulation. That isn't the cheapest way of using it but I hardly do stripboard layouts anymore. Its pre-tinned like the stuff in your link, stiff enough to hold its shape, but bendy enough to make neat tracks. I'm sure 0.3mm would be even easier to work with, and still be stiff enough to hold shape.

author: paulca
author_rank: Super Contributor
timestamp: January 31, 2018, 03:16:14 pm
content: I know what you mean, I use perf board to describe all of the above. They still might need links. However I'm currently working with double sided, tinned single pad boards as they seemed the easiest to solder for me.What I probably need next is to find sticky foam backing which can cover the ugly bits and mean it's unlikely to short itself out while kicking around the desk.
Perfect reusable Footprint/Adapter for 5V Dev Board power w/o space limitations - Page 1
Forum section: electronics / beginners

author: seveibar
author_rank: Newbie
timestamp: October 21, 2024, 06:18:34 pm
content: Hey everyone, trying to build a reusable power module to speed up some designs I'm doing. It doesn't matter how complicated it is because it's a code-to-cad module so even if it has 5+ components it's all zero-cost for me (I get boards fully assembled)I'm building a lot of dev boards/prototypes that just need power, they're more or less instructional boards for basic circuits. I was thinking the best module would have all of this:- Big pads for alligator clips- Screw terminals- Plated holes for female banana plug socket- USB-C, maybe with data broken out if neededI'm just trying to maximize how lazy i can be when powering these things up. Am I missing anything?
Peripheral device power switch and MCU sleep - Page 1
Forum section: electronics / beginners

author: Majek Ondrovic
author_rank: Contributor
timestamp: April 10, 2019, 10:01:13 pm
content: I have a project with an Atmega328pb at 3.3v 8MHz in communication with an SMD module ( a wireless lighting controller) over SPI. This whole project is lipo battery powered, and I want the MCU to sleep but remain powered so it can start almost instantly. The SMD module will need its power cut because it doesn't have a sleep mode- the module draws 60-250mAh variably.What is the ideal power switch in this case? A dedicated IC or some MOSFET, etc..?I've tested this manually by disconnecting the power to the module and then sleeping the mega328. I get about 8µA draw which is great. And then I have it wake up via an interrupt.My understanding was that putting all the GPIO to input with internal pull-ups gives the least current draw in sleep mode. But then I've noticed most of the power distribution switch IC's are all active high so I'm not sure how to best deal with that. I was hoping to be able to have the MCU come out of sleep and pull the power switch ENABLE low to turn the module on.Thanks in advance!
PFC boost transistor power loss calculation  - Page 1
Forum section: electronics / beginners

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 29, 2016, 12:03:26 pm
content: Hi,I want to ask about calculating power loss at PFC transistorswitching loss I can take from rms current, output voltage ad frequency (it is simple)but is here any simple formula to calculate conductive loss (average duty)?

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 29, 2016, 01:31:35 pm
content: I found this equation, results looks reasonable, but can please someone explain me where it come form ?

author: danadak
author_rank: Super Contributor
timestamp: March 29, 2016, 02:14:11 pm
content: I am thinking you cannot just use DC and load current to get at that,as that does not account for switching losses in power switch. Usuallythe vendor, like TI, have a simulator that will allow you to determine thatfor various loads. Even includes thermal considerations.Regards, Dana.

author: Miyuki
author_rank: Frequent Contributor
timestamp: March 29, 2016, 02:31:59 pm
content: Infineon converter design guide says that this simple equations are accurate enough𝑃𝑆.𝑜𝑛 = 0.5 ? 𝐼𝐿.𝑎𝑣𝑔 * 𝑉𝑜 * 𝑡𝑜𝑛 * 𝑓𝑃𝑆.𝑜𝑓𝑓 = 0.5 ? 𝐼𝐿.𝑎𝑣𝑔 * 𝑉𝑜 * 𝑡𝑜𝑓𝑓 * 𝑓and𝑃𝑆.𝑐𝑜𝑛𝑑 = 𝐼𝑆.𝑟𝑚𝑠2* 𝑅𝑜𝑛

author: danadak
author_rank: Super Contributor
timestamp: March 29, 2016, 07:24:33 pm
content: The equations seem to avoid the issue of gate drive Pdiss, but that would be OK ifId x Id x Rdson x DC dominates the overall dissipation.This might help -https://www.power.com/sites/default/files/product_document/application_note/AN-1001_IGBT_and_MOSFET_Drivers_Correctly_Calculated.pdfRegards, Dana.

author: orolo
author_rank: Frequent Contributor
timestamp: March 30, 2016, 02:03:09 pm
content: Quote from: Miyuki on March 29, 2016, 01:31:35 pmI'm no expert in this, in fact I'm a mathematician, not an EE, but the coefficients in your formula rang a bell, so perhaps I can help a bit.If you have a sinusoidal input current, $$V_{peak}\cos\omega t$$ and pass it trough an ideal rectifier, you get $$V_{peak} \vert \cos\omega t \vert$$. Taking the Fourier series of the rectified voltage, you get, to the second harmonic:$$ \frac{2V_{peak}}{\pi} + \frac{4V_{peak}}{3\pi}\cos 2\omega t + \ldots $$If your $V_{ac.min}$ is RMS, then, the input voltage is:$$\frac{2\sqrt{2}V_{ac.min}}{\pi} + \frac{4\sqrt{2}V_{ac.min}}{3\pi}\cos 2\omega t + \ldots $$The amplitude of the second harmonic is clearly recognizable in your formula, and in looks to be like a duty cycle format (disregarding efficiency, and taking the peak-to-peak voltage):$$ D = 1 - \frac{V_{in, min}}{V_o} = 1 - \frac{8\sqrt{2}V_{ac.min}}{3\pi V_o} $$So, somehow, your formula looks like:$$I_S = \frac{P_o}{V_{ac.min}}\sqrt{D}$$This is the part I don't really understand. I tried the computation for a normal booster, and found something along the lines of $$I_S = \frac{P_o}{V_{ac.min}}\cdot D^2$$ (continuous mode), so I don't know where the square root comes from. I also don't know why the zero-order harmonic doesn't come to play into the duty cycle, unless your output voltage equals the zero-order rectified voltage for some reason.Edits: LaTeX cleanup.
PFC Circuit PSIM error - Page 1
Forum section: electronics / beginners

author: dixhum
author_rank: Newbie
timestamp: June 11, 2025, 03:12:48 pm
content: Hello all ! I am learning PFC circuit for the first time. Using theBiricha's online digital PFC webinar(Screenshot attached), i have designed an equivalent circuit inPSIM simulation software. I have usedST PLDfor PFC control loop values. I have omitted the gains as mentioned in the webinar because this is simulation so sense values are ideal. The simulation result (screenshot attached) of this set up is PSIM error after few milli seconds (error - Error: One of the output values is out of the numerical range. This is most likely caused by a division operation where the denominator is 0.).I am trying to solve this for a month now, I tripled checked the control loop co-efficients, used PI block instead of 2p2z, added limiter after the 2p2z but same result, tried AI chat tools but no solution, tried many values of the controlled loop. My electronics knowledge is very basic , I feel like I am missing something fundamental. Today I decided to give up this venture but decided to give this one last shot. If any other information is needed then please let me know.
PFC sections of ATX power supplies - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 25, 2018, 11:23:18 pm
content: What exactly are they doing again ? Something with power triangles and getting the most resistive power output at any moment ? And mains is at 60Hz and PFC controllers switch at what frequencies >>10kHz ? Is it fixed or not? 60Hz is fixedDoes the PFC voltage vary from rectified mains to 2x or is it more or less fixed ? Maybe that's voltage mode and current mode fixes a current ?How do they differ from the following stage that usually switches a flyback transformer ? (They are just a boost converter ?)I know complex numbers no problem, but idk many eq's for elec's of this stuffWhy are they typically rated at +2x mains Vpeak, like +350V, when the intended overall output is only 5-12V ? What is the reason use a boost converter to 2x the voltage rather than say 1st use a buck converter and use 1/2 the voltage?Fire away thanks

author: wraper
author_rank: Unknown
timestamp: May 25, 2018, 11:27:50 pm
content: PFC is a boost converter with rectified AC on it's input. On the output it's a constant DC, usually around 400V.

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 25, 2018, 11:31:55 pm
content: I must learn againI do have the internet btw, it's just I'm asking as if in a room of people, because that might be easier than cracking the books, because I'm playing SC2 on brutal

author: wraper
author_rank: Unknown
timestamp: May 25, 2018, 11:32:18 pm
content: QuoteAnd how you will step down down, say, 30V during mains voltage cycle into 100V?
PFET power switch review - Page 1
Forum section: electronics / beginners

author: in06khattab
author_rank: Newbie
timestamp: July 10, 2024, 05:03:44 pm
content: Hi,Can you take a look and provide a review of this power circuit please?The button is a latching push button.The input can range between 6 and 20V. This is because the power could be 20V (USB C) or down to 6V (2 Li cells in series)

author: thm_w
author_rank: Super Contributor
timestamp: July 10, 2024, 10:23:24 pm
content: You are running SI7155 right at its absolute maximum gate voltage of 20V. Usually TVS would be closer to the fuse. Other than that it seems ok.Don't know if R1/C5 will really do anything.
PFF4N80 to FQPF4N80, possible?  - Page 1
Forum section: electronics / beginners

author: sarry86
author_rank: Contributor
timestamp: October 03, 2024, 02:08:07 pm
content: Hello everyone, can someone tell me if I can replace the PFF4N80 with FQPF4N80? Both are built on TO-220FP packages and there are minor differences like Drain source on resistance, Drain current, Power Dissipation etc, please help

author: thm_w
author_rank: Super Contributor
timestamp: October 03, 2024, 10:55:08 pm
content: https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/general-electronics-technical-discussion/3471396-replacing-pff4n80-with-fqpf4n80I can't even find the spec for PFF4N80, why not post those details here. and state what the application/product is and how much power it uses.Probably fine but we can't say for sure without more information.

author: Bryn
author_rank: Regular Contributor
timestamp: October 04, 2024, 08:07:54 am
content: Even though not much information was given regarding that query, I can say that the replacementispossible, despite the minor differences between the two (but it's best to ensure that the FQPF4N80 meet or go above the specs of the other component as to avoid any performance issues that may arise).

author: sarry86
author_rank: Contributor
timestamp: October 04, 2024, 11:56:41 am
content: I have attached the datasheets for both 🙏
pH glass electrode input path - Page 1
Forum section: electronics / beginners

author: analityk
author_rank: Regular Contributor
timestamp: May 12, 2024, 11:21:45 pm
content: Hello,how to build a reliable and still precise input buffer for pH glass electrode signals?In my new work i have notice that someone build realy crapy input for this purpose and it need to be changed. I do it in terms of leakage currents etc but input buffer opamp input bias current is lower than 5 pA.I have try measure voltage from glass pH probe with 10G input impedance multimeter but impedane is way to small to do this measurement.Anyway end user may touch probe and electrostatic discharge can fired up input opamps. How to properly secure inputh path from esd? Can i use some type of TVS with extremly low leakage currents?SincerelyPS:I have read this papers but definitely not found solution:https://www.ti.com/product/LMC6482https://www.ti.com/lit/ds/symlink/opa145.pdfhttps://www.mouser.pl/ProductDetail/Texas-Instruments/OPA928DR?qs=2wMNvWM5ZX5RgAZJHoeYSw%3D%3D

author: CaptDon
author_rank: Super Contributor
timestamp: May 13, 2024, 02:37:38 am
content: Maxim and several others make amplifier I.C.'s specifically for PH probe use. We used several and we powered them with 9vdc alkaline batteries. The batteries lasted for nearly their shelf life!! It has been a long time ago but I recall the probes we used came with BNC connectors.

author: Faranight
author_rank: Unknown
timestamp: May 13, 2024, 05:34:44 am
content: Back in the days I used anINA116for this purpose, which is a femtoamp instrumental opamp with included pins for guard rails, but the part has been NRND-ed since. See, if Texas Instruments offers any more up-to-date parts.

author: aliarifat794
author_rank: Regular Contributor
timestamp: May 13, 2024, 08:37:10 am
content: Your choice of op-amp with an input bias current below 5 pA is a good start. Op-amps like the LMC6482 or OPA145, are suitable candidates due to their low input bias currents.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 13, 2024, 12:54:07 pm
content: There are plenty of low bias OP-amps. It still needs a clean layout and board to avoid extra leakage, especially when the humidity goes up.For protection a high value (e.g. 470 K - 5 M) series resistor can do most of the protection. Most OP-amps have some internal diodes that are than sufficient. If needed bootstrapped low leakge diodes like BAV199 could be used as additional clamps.
Phase Angle Conventions - Page 1
Forum section: electronics / beginners

author: eev_carl
author_rank: Regular Contributor
timestamp: April 26, 2018, 02:34:56 pm
content: Hi,I have a simple series RC circuit: R=1k, C=.22, E=5Vpp 1kHz.I was wondering if someone could explain the difference between the phase angle on my scope and what I've computed as arctan(Xc/R). For arctan(Xc/R), I get -36 degrees and my scope shows 54 (Phase 1 ->2, where Es=1 and Ec=2). Hand calculating the scope's value w. cursors, I get 54 (td/period * 360).Update: Looking at this on paper, I think the scope is just using a different location for Ec. Rather than pointing down at 270 degrees, it's appearing at 0 for the reference. I'm still wondering which value is typically used when talking about phase.Thanks,Carl

author: bson
author_rank: Unknown
timestamp: April 27, 2018, 03:00:10 am
content: The AC phase angle is between voltage and current. Positive means the voltage leads (inductive), negative that the current leads (capacitive).

author: eev_carl
author_rank: Regular Contributor
timestamp: April 27, 2018, 01:33:00 pm
content: I read a little more on this. I wired my scope to measure Et and Ec and the displayed 54 degree value (td / period * 360) referred to that angle. I had expected the -36 value because my book examples showed the angle between Er and Et. I can get Er using a MATH function and get my -36.

author: schmitt trigger
author_rank: Super Contributor
timestamp: April 27, 2018, 01:37:35 pm
content: Quote from: bson on April 27, 2018, 03:00:10 amA simple way to memorize this:ELI the ICE man.

author: bson
author_rank: Unknown
timestamp: April 27, 2018, 09:11:00 pm
content: Quote from: eev_carl on April 27, 2018, 01:33:00 pmThat's interesting! All I can think of is that because C has a negative reactance its current is stated as flowing out of it rather than into it, which means Ic = -Ir, and if you measure Ir (by proxy, via Er) you need to reverse the sign for Ic. (More formally, you calculated the angle of the conjugate impedance, as if it were an inductor.) Hence, atan(Ic/Ec) = atan(-Ir/Ec) = atan(-(Et-Ec)/(R*Ec)). But that reasoning feels incomplete and kind of ad hoc, in particular because it seems to violate KCL.
phase detect circuitry - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: December 18, 2019, 02:17:18 am
content: How isclk_dccgenerated from the following phase detect circuitry ?

author: ataradov
author_rank: Super Contributor
timestamp: December 18, 2019, 02:48:36 am
content: It shows it right there with timing diagrams.They use either clk0 or clk180 as a clock for the D flip-flop. And the output of the flip-flop controls which one is used as an input.DFFs are often used to generate a 50/50 duty cycle, but the issue is that the output clock frequency is half of the source clock. This way they maintain the same clock frequency, since they use alternating phases as a clock source.This is pretty clever. Not sure how common this trick is, but I'm definitely stealing it.
Phase Frequency Detector without dead zone - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: June 29, 2019, 12:01:30 pm
content: How does the two inverter delay stage in Figure 6.14 on page 265 ofDesign of CMOS RF Integrated Circuits and Systemshelps to eliminate dead zone in Phase Frequency Detector ?

author: David Hess
author_rank: Super Contributor
timestamp: June 29, 2019, 04:01:40 pm
content: I think what is going on is that the delay to clear prevents a race condition where neither output is active in the dead zone. Instead, both outputs become active and the difference in timing between the two outputs determines the net output current.

author: Benta
author_rank: Super Contributor
timestamp: June 29, 2019, 05:42:45 pm
content: In a PFD, you need to feed the loop filter to keep the VCO stable. With an uncontrolled dead zone, you'll have a number of positive spikes, followed by a number of negative spikes, which causes jitter at the frequency of the loop filter response (=low frequency).By making certain that the output of the PFD always outputs alternating polarity pulses at input frequency when locked, the jitter frequency is equal to half the input frequency, which means it much higher than the loop filter cutoff frequency and thus negligible.Smart design, by the way.

author: promach
author_rank: Frequent Contributor
timestamp: June 30, 2019, 02:43:50 am
content: how does delay block after the 4-input NAND circuit determines the minimum width of the up- and down-pulses ?

author: hamster_nz
author_rank: Super Contributor
timestamp: June 30, 2019, 06:22:00 am
content: If you can think about these two questions, you will have your answer...How long does a signal take to propagate though a basic logic gate?What is the function of the signal that is being delayed? What does it do?

author: promach
author_rank: Frequent Contributor
timestamp: June 30, 2019, 06:35:47 am
content: The book version adapts the original version (Cell-Based Fully Integrated CMOS Frequency Synthesizers) with slight modification.Any idea why the book version does not require the feedback signal of DOWN signal ?

author: hamster_nz
author_rank: Super Contributor
timestamp: June 30, 2019, 07:23:32 am
content: Quote from: promach on June 30, 2019, 06:35:47 amDid you notice that the outputs are not named the same - the original picture has bit UP and DOWN being active low, and the later has active-high UP and an active low DOWN?

author: promach
author_rank: Frequent Contributor
timestamp: July 01, 2019, 07:46:55 am
content: How does the PFD deadzone-free circuit ensures that theSR latchesdo not enter metastable state ?I do not understand how the two SR latches in the middle region works. What are those two latches for ? Besides, what is the purpose of the 4-input NAND gate ?QuoteThe book author told me the above. What does it mean by "delay reset to guarantee min pulse width" ?
Phase Measurement in LT Spice - Page 1
Forum section: electronics / beginners

author: eev_carl
author_rank: Regular Contributor
timestamp: December 07, 2018, 02:07:38 pm
content: Hi,Am I applying this .meas directive correctly? I'm trying to get the phase angle between the two sine waves. On the scope, I measured this at about 80 degrees but am getting 63 degrees from .meas.Thanks,Carl

author: Ian.M
author_rank: Super Contributor
timestamp: December 07, 2018, 02:51:23 pm
content: Attach your sim as a .asc file so others can check it easily.

author: eev_carl
author_rank: Regular Contributor
timestamp: December 07, 2018, 03:10:56 pm
content: Here's my .asc

author: eev_carl
author_rank: Regular Contributor
timestamp: December 07, 2018, 03:16:17 pm
content: Also, with regards to the scope picture...the yellow sine wave is a direct connection from the function generator. I'm using a BNC splitter. The other half of the splitter goes to the circuit. The blue sine wave is at the junction of the R and the E.

author: Ian.M
author_rank: Super Contributor
timestamp: December 07, 2018, 04:01:12 pm
content: Why did you strip the .measure commands?Code:.meas TRAN TIME_1 TRIG V(Vin)=0 RISE=2 TARG V(Vin)=0 RISE=3.meas TRAN TIME_2 TRIG V(Vin)=0 RISE=2 TARG V(Vout)=0 RISE=2.meas phase param 360*(TIME_2/TIME_1)With the.tran 0 1m .5mcommand from the sim you attached, I am also getting about 80 deg, confirmed by cursor measurements. With your original.tran 50mI'm getting the same bogus 63 deg you got.I suspect the cause is too many cycles and not enough data points due to your initially ill-chosen simulation duration.

author: eev_carl
author_rank: Regular Contributor
timestamp: December 07, 2018, 04:48:49 pm
content: Sorry about the .meas. I posted the .asc before saving. Thanks for the note on the duration.

author: mikerj
author_rank: Super Contributor
timestamp: December 07, 2018, 05:08:44 pm
content: Quote from: Ian.M on December 07, 2018, 04:01:12 pmThe cause is the DC shift in the first few cycles. Ignoring this data by adding the 0.5ms recording start time fixes the problem rather than the simulation duration.
Phase modulation of RF signal - Page 1
Forum section: electronics / beginners

author: Yuri1737
author_rank: Newbie
timestamp: December 23, 2014, 11:54:01 pm
content: Hi,I need to modulate an 100-700MHz RF signal using Phase modulation schema. Does anyone now how to build a such a circuit? On the net i can find only fixed shifters.

author: VK5RC
author_rank: Unknown
timestamp: December 24, 2014, 06:16:01 am
content: Depends what sort of phase modulation, FM is a simple sort of PM and it is nicely not sensitive to harmonics, even AM and SSB can be thought of as a weird type of PM, but most PM now, eg digital radio, is complex and uses I and Q components often generated digitally.In amateur radio circles the HPSDR group are open source.Others on this group I am sure will provide further info.

author: AlfBaz
author_rank: Super Contributor
timestamp: December 24, 2014, 07:19:34 am
content: Alan, a member here, has a couple of videos on I Q modulation that may be of interest
Phase Noise vs spur free dynamic range - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: May 06, 2017, 01:16:23 am
content: I am looking at Keysight spectrum analysers and I dont understand the whole phase noise and spurious free dynamic range thing.I know what phase noise is,I also know what sfdr is,but I dont know which one is more important.For example,I am looking at 10khz sine wave that is -100db on scope that have 130db phase noise at 10khz and 75db sfdr,will I detect that sinewave?Another scenario,I want to measure phase noise of OCXO that have 100mhz sinewave output and phase noise -100db/10khz with scope with same specs like above,would it be able to accurately measure the phase noise of that clock?

author: w2aew
author_rank: Super Contributor
timestamp: May 06, 2017, 01:53:35 am
content: Quote from: fonograph on May 06, 2017, 01:16:23 amThese are spectrum analyzer specifications, not oscilloscope specifications in general. Are you sure you're looking at oscilloscopes?QuoteCan't answer this question. The value you quoted of -100db is not an absolute level, it is a relative level. A dB value is a measure of the ratio of a signal amplitude to another, not an absolute level. So, stating the signal level stated at -100dB doesn't tell us it's amplitude without giving a reference. The phase noise and SFDR specs are given in dB because is is usuall stated (or understood) that these values are relative to the input signal level. The ability of a spectrum analyzer to see a very small signal is dependent upon a few factors - SFDR is one of them, another is the DANL (displayed average noise level).QuoteMaybe. Phase noise is specified at various offset frequencies, usually for several different center frequencies. If the analyzer you're looking at has a spec for phase noise at 100MHz, measured at a 10kHz offset, spec of -130dBc/Hz, then IR will be able to measure the phase noise of an oscillator that is spec'd at -100dBc/Hz at a 10kHz offset.

author: fonograph
author_rank: Frequent Contributor
timestamp: May 06, 2017, 02:53:49 am
content: I made mistake,meant spectrum analysers not oscilloscopes.-100db from maximum value before clipping,I think its called dbfs,lets say the analyser can accept maximum +30dbm signal,then by "-100db" I meant -70dbm.If analyser have -75db SFDR,-130db phase noise/10khz and -175db DANL does that mean I can accurately measure harmonic distortion and intermodulation only down to -75db and noise to -130db if the bandwidth doesnt extend lower than 10khz?
Phase reversal? - Page 1
Forum section: electronics / beginners

author: liquibyte
author_rank: Frequent Contributor
timestamp: October 18, 2015, 03:52:33 pm
content: I've got a bit of a problem with this circuit and I'm not sure why it's happening. Sometimes when I power this up the voltage on the negative rail won't get above around 1.5V or so. If I turn it off and let the caps drain out and then turn it back on, everything is right with the world again and I can get my -18V. I've been hooked up to the scope (analog) on the output when this happens and it seems to be oscillating wildly but I can't figure out why it's happening and how to fix it. When things are working, they're working well with a nice waveform on the output. Am I running into phase reversal here or something else?

author: dmills
author_rank: Super Contributor
timestamp: October 18, 2015, 04:18:59 pm
content: I am suspicious about the startup behaviour of U2 (also potentially U1 for the same reason).In particular ask yourself what happens if U2 output momentarily swings above ground during startup (Which it can do due to the way it is powered), the dynamics are complicated, but I think see a possible instability or latch up.Try making the positive supply of U2 ground instead of +3V (And the negative supply of U1 ground instead of -3V).I think there are some words of wisdom in AOE (Second Ed) about this sort of self biasing arrangement and its lockup states.Regards, Dan.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 18, 2015, 06:34:13 pm
content: How about more decoupling on the power supply leads to the OP-07s? 100 nf right at the chips..... ?

author: liquibyte
author_rank: Frequent Contributor
timestamp: October 19, 2015, 05:19:59 am
content: Well folks, I screwed up. I should have run a final check of the boards because the zener regulator going to the negative rails op amps didn't have the trace connected to the resistor. This is a lesson that I won't soon forget. Double, triple, quadruple check your boards before having them manufactured. I feel like such a dumbass now.

author: dmills
author_rank: Super Contributor
timestamp: October 19, 2015, 10:08:46 am
content: Learn from it, and get ERC/DRC religion.The software should catch this stuff when you run the automated checks.Regards, Dan.
Phase sequence alert - Page 1
Forum section: electronics / beginners

author: vis5254
author_rank: Contributor
timestamp: June 12, 2019, 01:41:30 pm
content: Three phase line was directly given to resistor - Diode network and I obtained a pulsed output of 10v DC . 3 number of 10v pulse will have a delay between each other since we are dealing with three phase supply . When RYB was applied the Led was always turned on . Where as if its RBY , led would blink . What exactly these 4 NAND gates are doing with these 3 pulses to create this output . Please help . I'm a newbie . I know what's NAND gate , but cant figure out how these pulses do the action ?

author: soldar
author_rank: Super Contributor
timestamp: June 12, 2019, 01:56:14 pm
content: Why do you open a new thread when you already had one going?https://www.eevblog.com/forum/beginners/simple-phase-sequence-detector-using-nand-gate/
Phase Shift Oscillator - Page 1
Forum section: electronics / beginners

author: stitch
author_rank: Regular Contributor
timestamp: January 12, 2012, 04:40:28 am
content: I can understand the source of oscillations in a Colpitts oscillator (the tapped tank circuit). But I am having difficulty understanding the source of oscillations in a phase shift oscillator. I do see a feedback path in a phase shift oscillator, but where do the oscillations come from? Thank you.

author: IanB
author_rank: Super Contributor
timestamp: January 12, 2012, 04:52:09 am
content: To have oscillations you need positive feedback.Supposing your oscillator output is going to be a sine wave, then if you shift a sine wave by 180 degrees it will look like an inverted form of the original wave. So take that wave, shift it by 180 degrees and then feed it to the inverting input of an amplifier and you will have positive feedback. Voila! You have oscillation.

author: stitch
author_rank: Regular Contributor
timestamp: January 12, 2012, 05:17:38 am
content: Thank you IanB. But what is the source of the sine wave that you mention? Where did the sine wave come from in the first place?

author: ejeffrey
author_rank: Super Contributor
timestamp: January 12, 2012, 07:46:25 am
content: Noise. There is always a small amount of broadband noise present due to the amplifier input noise or the resistor johnson noise. The noise at the selected frequency is amplified each time it goes through the feedback loop until it gets to be full-scale.Some types of oscillators actually do have trouble starting up in a reasonable amount of time. In that case, injecting some signal from an external source may help things get going.

author: stitch
author_rank: Regular Contributor
timestamp: January 12, 2012, 05:57:20 pm
content: Thank you, ejeffrey. That is the missing link I was looking for.

author: w2aew
author_rank: Super Contributor
timestamp: January 12, 2012, 10:05:07 pm
content: Quote from: ejeffrey on January 12, 2012, 07:46:25 amThis is precisely why is sometimes is difficult to simulate these types of oscillators - because there might not be enough numerical rounding (noise) to get the oscillation started. For these circuits, one often has to apply a transient or use some other initial conditions to get "things moving"...

author: Zero999
author_rank: Super Contributor
timestamp: January 13, 2012, 10:16:53 pm
content: Quote from: w2aew on January 12, 2012, 10:05:07 pmYes, that's true for many circuit. In LTSpice the easiest way to do this is to skip the initial operating point calculation which means the power supply voltage is suddenly applied, charging up all the capacitors, rather than the simulator figuring out the DC voltages around the circuit before starting the simulation.
Phase Shifting Circuit - Page 1
Forum section: electronics / beginners

author: derGraph
author_rank: Newbie
timestamp: August 13, 2020, 08:53:31 pm
content: Hi, I need a circuit to phase shift a 300khz Square wave 0°-180° (with an analog input signal). It could be a simple Circuit or an IC.Thanks Paul and Felix

author: David Hess
author_rank: Super Contributor
timestamp: August 13, 2020, 10:51:37 pm
content: Phased locked loops are good at that. Otherwise if the frequency is fixed, then a voltage variable delay will achieve the same thing.

author: ledtester
author_rank: Super Contributor
timestamp: August 19, 2020, 11:58:00 pm
content: If it would work for you I would use a microcontroller. The atmega328 (the brains of an Arduino) could do this easily by simply altering the output compare registers to correspond to the delay time.Otherwise you need a voltage-controlled delayed-pulse generator. There's an EDN Design Idea for such a circuit in the April 17, 2008 issue, page 98:https://archive.org/details/EDN20080417/page/n97/mode/2upThen you still need a monostable multivibrator, like the CD4098.
Philips PE1542 transformer hum - Page 1
Forum section: electronics / beginners

author: Bskitter
author_rank: Regular Contributor
timestamp: September 20, 2016, 09:07:40 pm
content: Hello Guys,I purchased a Philips PE1542 of ebay a few months ago and the transformer has a hum/buzz to it.So I spoke to an old repair guy and he mentioned that sometime boiling wax in a pot and dropping the whole transformer in the boiling wax for 10 minutes could fix it.I also read that dropping the transformer in wood shellac mixed with methylated spirits could get rid of the hum.What are your views on this ?Secondly, can a faulty cap cause a hum on the transformer ?Byron

author: danadak
author_rank: Super Contributor
timestamp: September 20, 2016, 11:48:59 pm
content: yes to the faulty cap, if it is drawing a lot of excess current abovethe reactance value. Eg. shorted or close to it.Regards, Dana.

author: Bskitter
author_rank: Regular Contributor
timestamp: September 21, 2016, 12:27:56 am
content: Thanks for the tip Dana,Ill disconnect the cap and see if the hum fades away.These large value caps are quite pricey.

author: oldway
author_rank: Super Contributor
timestamp: September 21, 2016, 06:18:06 am
content: A faulty capacitor can not cause transformer hum.What fault of the capacitor?Generally, electrolytic capacitors lose their capacitance and it can not cause the hum of the transformer.If short circuited, the capacitor will blow the fuse.High leakage current is also impossible because the capacitor heat up tremendously and explode in a short time.By cons, this can be caused by a faulty diode bridge with an open diode.Try to check if the transformer continues to produce hum with secondary connections disconnected.Does the transformer works abnormally hot without load?Have you tried to tighten the bolts of the laminations?To impregnate the transformer again, use a special varnish for this use.
Philips PM 3216 oscilloscope - Page 1
Forum section: electronics / beginners

author: africanrobert
author_rank: Newbie
timestamp: July 23, 2018, 06:09:39 am
content: New to this site - please advise if I'm posting wrongly.Scope PM 3216 worked well, but not been used these last 20 years.Powered up today, and found no horizontal/X scanning at all. Regardless of settings.The Y section noted ok by injecting noise.Have no data available at all- would appreciate any advice.

author: Simon123
author_rank: Regular Contributor
timestamp: July 23, 2018, 11:39:07 am
content: Try injecting signal in X input while in XY mode.
Philips PM 3233 not working - Page 1
Forum section: electronics / beginners

author: Nejdet
author_rank: Newbie
timestamp: October 20, 2022, 07:20:57 am
content: Hi, I'm new to this forum. I recently bought a non-working oscilloscope Philips PM 3233 - the problem is missing secondary voltages at the output of L 802. The two transistors TS 806 and TS 807 heat up! I think the L 802 is defective. All diodes are working after L 802 and there is no short circuit after them. My question is, can I find data for the L 802 from somewhere. Thanks!
Philips PM 3580 / 30 - Page 1
Forum section: electronics / beginners

author: Ghitza
author_rank: Contributor
timestamp: June 07, 2021, 04:48:35 pm
content: Hi guys,is it worth paying 135€ for such a logic analyzer? I already saw it and it looks very nice with all the accesories that was in the box as new.I'm not a Pro like most users of this forum but I almost daily study the electronics since for me it is a hobby and I wanna learn it better.Does this has any use this days? It has 2 pods with hook grabbers and they are excelent designed compared to the chinese one on the market.Also there are 2 floppy discs with sysrem software 2.01 in english and german. It is my neighbour and he asked me before set it on ebay.Thank you very much.
Philips PM3215 12V AC between scope GND and earth??? - Page 1
Forum section: electronics / beginners

author: Bond
author_rank: Newbie
timestamp: July 17, 2023, 07:01:25 pm
content: I've recently bought a Philips PM3215, first thing I did was open it up to check the caps and as expected the original Rifa was still in there. I substituted the X1 with a Y2 and powered up the scope. Since this scope is floating (by design not by me) I wanted to make sure touching the scope wasn't going to kill me so I measured the potential difference between scope GND and earth, to my surprise I measured ~12V AC. It this normal/safe or can this potentially damage other equipment I connect it to?While testing it again to grab a pic to attach here and I didn't even have to turn on the scope, just plug it in.

author: wasedadoc
author_rank: Super Contributor
timestamp: July 17, 2023, 07:10:50 pm
content: Set your meter to measure alternating current. How many milliamps does it show when connected between scope ground and earth?

author: Bond
author_rank: Newbie
timestamp: July 17, 2023, 07:25:47 pm
content: I hadn't tested this yet because I was scared to trip the GFCI.Just measured it at 1.6uA so I'm assuming this is normal and 100% safe :p

author: m k
author_rank: Super Contributor
timestamp: July 20, 2023, 04:47:28 pm
content: So around 7.5Mohms, not bad.Truly floating means that machine ground and grid earth are not connected.So in theory you can measure almost what ever.But there's a but, frame is grounded.So do not invert the picture by swapping passive probe polarity.
Philips PM3219 CRT - Page 1
Forum section: electronics / beginners

author: Ghitza
author_rank: Contributor
timestamp: May 17, 2021, 08:01:15 am
content: Hi guys,I've purchased this unit for 20 euro. What can you tell me, please, about the CRT?Is it damaged or not? Does it worth to try a repair on this unit?Thank you very much!

author: tunk
author_rank: Super Contributor
timestamp: May 17, 2021, 11:11:16 am
content: No expert on this - but did you turn the "intens" to max?And I'm sure you know it takes some seconds before there's anything on the screen.

author: Gyro
author_rank: Super Contributor
timestamp: May 17, 2021, 11:36:15 am
content: That's an Analogue storage scope. Depending on control settings you will get things like fully illuminated screen from the flood gun. You should download the manual for the scope to understand the functions of the storage controls.I can't see enough of the controls, but you will be able to turn storage mode off and use it as a normal scope.EDIT: Service manual:https://www.opweb.de/english/company/Philips/PM3219Service manuals usually contain operating instructions too. Eur20 for a 50MHz scope isn't bad.