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  1. Rleo6965

    Help identifying components

    Do you have idea what kind of board was arcnet you want to recreate? I have experienced with arcnet network card before and that very old network topology.
  2. Rleo6965

    Sensor for Human detection

    You can use proximity sensors.
  3. Rleo6965

    Power Trip when probing Oscilloscope..

    Isolation transformer? That's very good advice. Buy one for your safe trouble shooting AC source devices or pwm device and your test equipment. Wish I can replace my 15 year old Leader 1021 Oscilloscope with Tektronix TDS2012.:D
  4. Rleo6965

    Need help with 12 volt charging system please

    Check the dc voltage on the battery to see if it charging with 13V while the engine was running.
  5. Rleo6965

    What can I do with this?

    This is only for wireless RS232 communication between 2 device within a short distance. It's not capable to transmit hi fidelity audio signals.
  6. Rleo6965

    Power Trip when probing Oscilloscope..

    Oscilloscope test probe were high impedance and should not affect or loading the output of uc3525. What kind of oscilloscope your using? I use old model oscilloscope and I removed the Ground pin of AC plug so Oscilloscope Gnd connection will be floating. This to avoid loading or disturb the...
  7. Rleo6965

    Cheking PWM on board???

    If you don't have oscilloscope. You can use multimeter with Frequency function. Most pwm ic run on 20khz on output pin of uc3845 and some higher..
  8. Rleo6965

    220v LED DIMMER??

    The circuit seems will work. It has capacity of 600 watts. You can use NE555 Astable circuit with variable output pulse width. Just wondering that your unaware of that circuit diagram? Possibly sent by virus program.:D
  9. Rleo6965

    dual rail supply and ground

    Place bigger wires for +V, -V and GND and as short as possible between IC regulators and Output Jack. Solder R2 and R3 to Output and GND terminal of IC voltage regulators. This is to avoid voltage drop on wires and better voltage regulation.
  10. Rleo6965

    tci ignition problem

    How about post the other side of the board. It will help us more identifying possible defective components. Post bigger picture on 2 transistor side.
  11. Rleo6965

    tci ignition problem

    Its possible that you have defective power transistor and protection diode. Much better that you check using multimeter to isolate or test which of those component was shorted. Compare collector and emiiter of 2 power transistor. Transistor with very low or zero ohms reading was therefore...
  12. Rleo6965

    best electronic circuit simulator

    Circuit Wizard for beginners. LtSpice IV for experienced in Electronics.
  13. Rleo6965

    pc power supply

    You can isolate if motherboard was causing the problem by installing 2 hardisk only without the mother board. Place jumper wire on dc connector green and black wire. If problem still the same. Possible cold solder was causing intermittent problem of power supply. You need a magnifying glass to...
  14. Rleo6965

    3V to high voltage inverter

    If all component were correct and still not working. Reverse the winding of L1.
  15. Rleo6965

    Finding powe supply polarity from the circuit board?

    I agree with GreenGiant. Its centre +VE. Negative side of Capacitor was soldered on etch of PCB. Follow the trace and this lead you to negative of Plug. See photo.
  16. Rleo6965

    Model engineer needs help

    It will only feedback +0.01V. Do you think it already enough?
  17. Rleo6965

    Model engineer needs help

    Chris, I'm not sure about this. Do you think that R16 1M will do some voltage feedback or hysteresis effect to pin 5 input of opamp?:confused:
  18. Rleo6965

    Read value of SMD diode (mini-melf)

    Show me first correct drawing and I'll try to explain.
  19. Rleo6965

    Read value of SMD diode (mini-melf)

    Feedback circuit not function if dc output goes to 0V with load. Check again TL431 , Opto isolator and other components that connects to Gate of Power FET. It's better that you draw that feedback circuit for proper analysis.
  20. Rleo6965

    Read value of SMD diode (mini-melf)

    Where was 1P smd transistor connected? I suggest that you complete drawing the TL431 voltage reference circuit. This circuit feedback signal to inverter if voltage slightly drop from its normal dc output.. Inverter circuit will therefore correct it output voltage. This is the reason dc output...
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