Free Simple Circuit Diagram
Colpitts oscillator can be implemented using op-amp as long as we have an op-amp with proper bandwidth. Here is an example of such circuit: LT1190 or LT1191 op-amps is used to serve as an excellent gain stages. Limiting the gain is done by two Schottky diodes, that maintain the signal at approximately +11dBm. This circuit give a low distortion performance, […]
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PLL (Phase Locked Loop) can be used to make a FM demodulator. PLL circuit track the input frequency by controlling a voltage input of a VCO (Voltage-Controlled Oscillator). Since the VCO is controlled to follow the input frequency, then the controlling signal is directly proportional to the modulating signal. Here is the schematic diagram of the cicuit: For this example, […]
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The FM transmitter circuit here works in the broadcast band 88 to 108MHz, and can be used to broadcast audio signals for remote listening. The output power is around -21dBm, and the circuit operates with 3V power supply. Here is the schematic diagram of the circuit: If you want to carry out your portable sound system around the house, this […]
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Antenna Booster Circuit This antenna signal booster works for TV receiver in UHF band (400-850MHz). This antenna booster gives around 10 to 15 dB amplification. Here is the schematic diagram of the circuit: This antenna amplifier circuit need special attention for the layout, the transistor circuits should be shielded from the input circuit (as shown with the dashed line), and […]
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