Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.


  1. B

    Building a very simple capacitor bridge-rectifier power supply

    Okay. I found other similar posts, but in them I haven't found the kind of answers I need. I am building a very simple low amperage 300vdc power supply using a 115vac source, to a switch, to a 370vac 80uf single Run Capacitor, to a 500v bridge-rectifier, to 300+vdc output cord and connectors to...
  2. D

    Gas fire Remote repair. Think it's a capacitor

    Hi, Im trying to fix a remote for a gas fire but I'm quite inexperienced, I think I've narrowed down the problem to a capacitor, Im not sure what capacitor it is or where to get a replacement, the chip the capacitor is connected to gets hot when I attach a battery to the circuit but nothing...
  3. S

    Thin sheet of semiconductor in a dielectric-filled capacitor

    Hi all, I have a question regarding modifications to a "standard" plate-capacitor with plate area A, plate distance d and filled with a dielectric. The equations for capacitance and electric field in this case are well known. I found examples for what happens when inserting a thin conductor...
  4. M

    Fixing a Siemens Induction Hob

    Hello Friends, I'm new to the forum and rather a noob in relation to electronics math. I own a Siemens Induction Hob model number: EX675JYW1E/01, which recently raised plastic smelling smoke while I used it. After opening the device's enclosure with an electrician, we found that one...
  5. B

    Voltage loss of capacitor

    Hi Guys, One of the tests that i have been requested to do by my manager in order to validate a capacitor is to measure the voltage loss across the capacitor, does anyone have an idea how to do that? thank you in advance
  6. E

    electronics devices 1990 store for not failed electrolytic capacitors

    I have old electronic devices from 1990 saved What is your recommendation for the storage period without the electrolytic capacitors failing due to disuse? I asked manufacturers and they didn't answer or they were confused
  7. R

    Ideas for a capacitor bank for a tesla coil??

    I've built a few tesla coils before, one solid state coil and one flyback tesla coil, however I'm looking to build a new one. I have (as mentioned in a previous post), a surplus of old tubes. I also found a bunch (20-30) of old vacuum capacitors rated for 20kV, they are the adjustable/tunable...
  8. A

    Bypass capacitor

    Experimenting with 10mm mini motor w/linear screw, 4 wire, 5VDC & wondering if a bypass capacitor is feasible for direct drive, no controller? If yes, what size cap is appropriate? Here's the unit: https://www.ebay.com/itm/383717016058
  9. J

    Changing flashing LED on module to stay on - use a capacitor? Any help please?

    I'm coming from a programming background and although I'm doing more electronics recently I'm still very much learning. I'm using a bluetooth module (this one **broken link removed**) It has an LED function but it's really annoying. It blinks quickly when bluetooth is not connected, and blinks...
  10. V

    LED + Battery without fading

    Hello everyone, I'm searching for help since electronics are not my field of study... I'm trying to build a simple project that requires an LED with a constant light output (the LED must be wired to a coin battery cell i.e. CR2032). When reading the LUX from the LED I can see the LUX decreasing...
  11. C

    What frequency value to use to find the correct time constant for a 22kΩ resistor?

    Hey guys, I have just been introduced to time constants and I'm having some trouble with this question. What frequency value do you plan to use to obtain the correct time constant for a 22 kΩ resistor? (Hint: It takes five time constants for a capacitor to go through the full charging...
  12. K

    Help identifying strange capacitor terminal style

    Greetings! I've run across a very strange terminal type for a capacitor, that I've never seen before. Anyone able to help identify the terminal style? It will get me closer to finding out if it's a source able part. Thanks! Sorry that I don't have a picture from the bottom. This is what I...
  13. J

    SMD Electrolytic Capacitor: Decoding Capacitance & Voltage Rating

    I have an old accelerator board used in the PDS slot of an Apple Macintosh SE/30. The board was manufactured around 1994. I want to replace the electrolytic capacitors but I'm not sure how to decode the numbers printed on the caps. Here's a photo: As you can see the numbers are: 22 6 A...
  14. sr13579

    How to make a simple oscillator with transistor and Capacitor?

    I provided a circuit which should discharge at a specific time. But this circuit is not working as an oscillator. How should I make circuit which will give me oscillation?
  15. A

    Power Board on a Flat screen TV

    I'm working on a flat screen tv it had 7 capacitor blown i replaced 6 of them already but the 7th one i dont have on hand (680uf 25v 105*c VENT) can i use a (1000uf 25v 105*c VENT) instead?
  16. Â

    Transient circuit

    My college professor asked us to take a real life problem/device and design and solve its circuit using transient response and Laplace transforms. It has to be a simple circuit, maybe just some capacitors, power source, switch and resistors... My biggest problem is finding a connection to a real...
  17. H

    Using Capacitors as Energy storage device - eliminating the phase differ between voltage & current

    I constantly read that capacitors provide reactive power. So how are they used instead of a battery? I mean in a battery the voltage and current are in the same phase. How is the phase change between the voltage and current in a capacitor eliminated without using an inductor, to use capacitor as...
  18. E

    LCR meter and ESR for small capacitors

    Hi. I've bought my first LCR meter, capable of testing at 100 Hz to 100 kHz. It can measure ESR in Cs mode (capacitance, series measurement). For electrolytics, it seems to work fine. But, if test a good 100 nF ceramic capacitor, it measures hundreds of ohms resistance, which it obviously must...
  19. Adam Binder Rogacki

    What capacitor to use?

    Hello, I can't find anything about what capacitor to supply to a circuit. And why to supply it to a circuit. If I e.g have a circuit with a battery and a led, the battey is 3.2v, and the led's forward voltage is 2v, and the current limit is 20mA to the led. Oh, and what happens when a capacitor...
  20. J

    Help! LCD Repair - Repairing a Homedics Digital Bathroom Scale

    Hi ladies and gentlemen, I was wondering if any of you could help me with a repair on an electronic bathroom scale. The brand is Homedics and the model number is SC-476. It is no longer under warranty, so that's not an option, unfortunately. I tripped and fell walking into the bathroom, right...
  21. W

    Charge of two capacitors in parallel, should be easy.

    It should be easy. It is about a 12V DC source and two triplets resistance-capacitor-resistance in parallel. The theory and spice predict that in the long run ( many times more than 10*R*C), the two capacitors will charge at 12V, but in practice, only one does! C = 0.33uF for each triplet, each...
  22. Clarkdale44

    Look at the schematic...

    **broken link removed** What's the use of 5th diode in this schematic..(which is in parallel with cap)? This is a circuit to drive led from mains AC. Sorry if this question is too simple or obvious.. I just want to know what that diode's doing there.
  23. W

    Capacitor Selection For A Dummy

    I'm truly very clueless about electrical circuits and I'm hoping to get some help. I'm told I have some AC ripple in my DC power lines, so here I am looking for some help. Here is a brief summary of what I have. I'm using the following part to get a 24V DC output...
  24. throbscottle

    Doorknob capacitor substitutes

    I probably need to replace a 16KV, 470pF doorknob type capacitor. They are very expensive, so I was thinking of putting 2x 10KV, 1nF ceramic disk type caps in series, which is much cheaper. Then my brain eventually ground round to the idea of hollowing out the original cap and putting the disk...
  25. S

    Help Needed! Rectifier Circuit

    Hi, I am currently working on a passive rectifier circuit for an implantable device. I was wondering if anyone could tell me the equivalent impedence/resistance before the diodes in the circuit i.e. nodes x, y in the attached image. Is there an expression that can be stated for all rectifiers...