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  1. audioguru2

    12 to 220V 200Watts Power Inverter

    The schematic is a 10M bitmap and is more than double the size of my screen. I reduced it to 40% size in MS Paint and saved it as a very clear 86k PNG file.
  2. audioguru2

    Matching IR-components

    I don't know how much power and what is the distance of your laserdiode. I also don't know how much laser energy would burn your BPW40. It is a visible light system that works only at night in the dark! Unless the range is very short and the phototransistor is shaded very well.
  3. audioguru2

    Digital radar speedometer

    The laser receiving diode is wired so that it is forward biased and is conducting all the time. I don't see how it can give an output.
  4. audioguru2

    Matching IR-components

    You have a visible light phototransistor in a clear case. It operates at 50% with IR from your IR emitter. You should use an IR phototransistor that usually are in a black case which is a filter for visible light.
  5. audioguru2

    audioguru, question on preamp/amp

    Hi Crivoli, An amplifier has positive feedback squealing when it has a microphone that can hear its speaker. Turn down the volume, reduce the gain or separate them. An amplifier (especially with a very low power output like an LM386) produces very bad quality when its output clips because its...
  6. audioguru2

    H-Bridge COmplementary Transistors--Plz help in selecting them

    Hi Shaiq, Now the circuit is connected correctly. The gates of the Mosfets now have 10.9V and 11.9V. Make certain that the logic inputs are a steady DC and are not pulses. Since the LED blinks and is dim and the motor vibrates and doesn't run then your power supply can't provide enough current...
  7. audioguru2

    H-Bridge COmplementary Transistors--Plz help in selecting them

    Hi Shaiq, You have the source leads of the P-channel Mosfets connected to the motor. The drains should connect to the motor and the sources should connect to +12V.
  8. audioguru2

    simple FM transmitter.

    Hi MNA, I didn't provide a link to our project because I want Silicon to look at the many projects there.
  9. audioguru2

    simple FM transmitter.

    This one is from our Projects section (RF Circuits) and is very simple. Too simple because its radio frequency will change if something gets near it, if its battery voltage gets less and if the temperature changes. It doesn't have the treble boost that FM and TV stations have so its sound will...
  10. audioguru2

    help me!!about a mixer

    The volume control pots should have an audio taper, not linear. 10k is about the most common value for a volume control pot, but a 20k pot will work the same in that circuit.
  11. audioguru2

    Power Supply Project needed

    The voltage regulator in an LM3914 is to provide a stable reference voltage for its comparators. Whan it is loaded then the LEDs become brighter. An emitter-follower transistor can be used to feed a regulated voltage to something else. The LEDs don't need a voltage regulator because each LED...
  12. audioguru2

    Simple help with transistors!!

    I understand that the contacts on the switch that turns on the lights and the contacts on the lights are difficult to reach. Therefore you want to sense that lights are on by detecting current in the fuse. Right? The fuse that you want to measure current in will have a very small voltage across...
  13. audioguru2

    Simple help with transistors!!

    I have no idea what you need.  How much current does your load draw? A transistor needs a small input current to switch a high output current. A Mosfet can switch a very high current and is cheaper than a relay. Its input current is zero.
  14. audioguru2

    Simple help with transistors!!

  15. audioguru2

    Power Supply Project needed

    The problem is that the opamp's input voltages far exceed their common-mode voltage limit which is a few volts less thas the opamp's supply voltage. You should use voltage dividers to reduce the input voltages. Why not use an LM3914 bar-graph IC? It has a programmable voltage reference, 10...
  16. audioguru2

    Quick fan speed question

    It might be the output of a speed sensor.
  17. audioguru2

    H-Bridge COmplementary Transistors--Plz help in selecting them

    Hi Shaiq, A Mosfet H-bridge driver IC is much better because it has dead-time when it switches to guarantee that an N-channel and a P-channel Mosfet that are in series across the supply are not both turned on at the same time. It looks like your circuot doesn't have dead-time so will momentarily...
  18. audioguru2

    0-30 Vdc Stabilized Power Supply

    Yes. Then it can be bolted to the chassis as its heatsink. The same pcb is fine. A few larger resistors will need to be spaced above the board. Q1 will need its pins bent around. Q2 can be bolted to the heatsink and won't need an insulatopr and the Q4's are also without insulators. Then insulate...
  19. audioguru2

    H-Bridge COmplementary Transistors--Plz help in selecting them

    Hi Shaiq, I used an old IRF540 Mosfet to drive an 8A motor and it barely got warm. I don't know what you can buy in your country so just pick a matching 33A P-channel Mosfet.
  20. audioguru2

    0-30 Vdc Stabilized Power Supply

    Good! ;D
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