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  1. R

    amplify the power (infrared)

    I connected the pin4 to ground already and the signal was amplified.  The problem occur at receiver or transmitter?  Or the output power of the transmitter insufficient?
  2. R

    amplify the power (infrared)

    R1 = 470ohm; C1 = 0.1uF; R2 = 1kohm; R3 = 10kohm; IC = LM324
  3. R

    amplify the power (infrared)

    but my project requirement must use AM to transmit the audio signal.  How can i amplify the power and increase the distance???
  4. R

    amplify the power (infrared)

    Sorry, this circuit is old version.  I changed the frequency to the 38kHz already.  But the distance between the transmitter and the receiver is very short.  How can i increase the distance?  increase the power? I don't know how to increase it.
  5. R

    amplify the power (infrared)

    I would like to use this circuit to transmit the audio signal.
  6. R

    KA2184

    i would like to find the datasheet please help me~~~
  7. R

    Audio amplifier

    Any audio amplifier (Mono)  circuit can drive a earphone?  The impedance of the earphone is about 16ohm. Thank you.
  8. R

    9V power source

    My project is infrared headphone.  I would like to supply 9V for my circuit but I do not like to use 9V battery (1.5Vx6).  Any suggestion about it. Thx~~~
  9. R

    infrared transmittion

    but this signal can transmit to the receiver using infrared???
  10. R

    infrared transmittion

    the output is like this figure, can i transmit this signal to the receiver?
  11. R

    infrared transmittion

    I want to use the IR diode to transmit the modulation signal to the receiver.  I constructed this circuit and connect two IR Diode on the output(Vmod).    I tested the IR diode using CRO, there has the modulation signal.  But the receiver can not receive the signal.  Is this circuit has any...
  12. R

    About analog Multiplier

    May I design a analog multiplier circuit without AD633 IC?  complex?
  13. R

    About analog Multiplier

    Hello everybody, I want to make a analog multiplier to multiply two audio signals.
  14. R

    Mixer

    And can you suggest some circuit that can generate the 40kHz? Wien-bridge oscillator?
  15. R

    Mixer

    I want to use the amplitude modulation and the carrier frequency is 40kHz In my project, I would like to tansmit the carrier and the audio signal by infrared.  At the receiver side, I would like to use the envelope detector to take the original audio signal.
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    Mixer

    hello~~~ I would like to multiply the carrier and  the audio signal.  And I want to design the mixer to multiplier these two signal.  What can I do?? can I use the summing amplifier???
  17. R

    Infrared Transmission

    hello everybody~~~ I would like to design the circuit.
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