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  1. Rleo6965

    Identifying problem source

    Have you tried check the dc output of power supply out of the flat computer screen assembly?
  2. Rleo6965

    555 TIMER - Trigger Pin 2 Voltage??

    Just remember. Any voltage of input pin2 goes lower than the 1/3 volt of vcc will trigger or change he state of pin 3 output.
  3. Rleo6965

    What epoxy used for encapsulating pcb?

    It seems MG Chemicals 832B Black Encapsulating product suits my requirement. Already request quotation in Mouser Singapore. Next problem to solve was the Aluminum Die Cast Casing. It's very expensive if bought internationally. It seems I have to look for local Aluminum fabricator. Hope I can DIY...
  4. Rleo6965

    What epoxy used for encapsulating pcb?

    My purpose was to hide component on pcb , mechanically hard to removed conformal coating, no corrosive chemical properties and can withstand at least 600V. So it must not "clear epoxy" and can't be easily removed using hot air tool. I took me 6 months to developed the cdis circuits and I don't...
  5. Rleo6965

    What epoxy used for encapsulating pcb?

    Saw a picture of encapsule pcb board in another thread. I want also to encapsule secret circuit on a small pcb to protect my design so that it can not be easily copied. It's about 2"X2 1/2" pcb. Can somebody give me the name of brand of this kind of epoxy. Thanks in advance. It's the...
  6. Rleo6965

    How to find short on PCB

    Usually with that kind of problem. First I have to isolate which part of the board causing to blowing of fuse. I removed the power transistor or chopper and the inverter IC or board. Replaced the fuse with half the current capacity of the original fuse. Then place a voltmeter on +V of bridge...
  7. Rleo6965

    The frequency to make us sleep?

    If you can simulate the sound inside the car while cruising on a highway might also help.
  8. Rleo6965

    IGBT ignition coil driver

    Signal turn off will be done by pull down 56K on base of transistor. uC only turn on the transistor.
  9. Rleo6965

    How this circuit works ?

    Your lucky that simulation software and datasheet readily available in internet today. Before we have to memorize every component and circuit and simulate the circuit in our memory. Sometimes our brain also hang up or temporarily blackout if circuit was too complicated.:D
  10. Rleo6965

    Circuit Board clean up question.

    One technique that I use was to place the solder sucker on opposite side of pcb and place soldering iron on top side. Once solder already melt solder sucker suck the liquified solder under the pcb and clear the hole. I also place a 3/8" length of carburator vacuum hose on tip of solder sucker...
  11. Rleo6965

    How this circuit works ?

    That means his a very good circuit analyzer.:)
  12. Rleo6965

    IGBT ignition coil driver

    That diode surely give you peace of mind if transistor and driver becomes shorted.
  13. Rleo6965

    IGBT ignition coil driver

    Diode should be in series w/ 1k resistor not in parallel.:)
  14. Rleo6965

    IGBT ignition coil driver

    If you want to protect 16F628A in event BIB373 was shorted. Place 1N4148 or equivalent in series with 1k resistor and connect 56k resistor in replace with 1n capacitor. Connect anode of diode to output pin of controller.
  15. Rleo6965

    DC power supply

    Vick5821 This a test for you. Draw the diagram of LM317 using spst switches. I'm still figuring out how to do it. But it can be done.:)
  16. Rleo6965

    how to use

    Did you place a capacitor in series with the tweeters or you directly connect the tweeter on speaker wire? Purpose of capacitor in series was to allow only high frequency to pass and drive the tweeter. Without the capacitor , Low frequency or bass sound will drive directly thin voice coil of...
  17. Rleo6965

    Tachometer Signal Modification Circuit Help

    0.5 V was negligible and hard to amplify to larger signal. Noise might distort the signal. How about add your own magnetic sensor and place magnet on motor shaft. You might find good magnetic sensor in Ebay.
  18. Rleo6965

    Upgrading amps of a circuit to 12A

    Have you tried reducing first the dc voltage and the electric car Starting mode. Once car have momentum then switch to +12V.
  19. Rleo6965

    DC power supply

    If circuit have power on. Vin ( +20V) always higher than Vout (+12V). Vin was 8V higher o than Vout. That is diode will be reverse biased and no current will flow on diode. Once power off. Vin voltage will become lower. Vout without load will have +12V. Vout therefore was higher with respect...
  20. Rleo6965

    DC power supply

    The purpose of diode was discharge path for existing charge voltage on Cout and bypassing IC regulator. Cout Voltage exist if output have no load.
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