This dynamic compressor circuit that The reduction rate of the signal up to 20 dB at input between 100 mV to 10 volts. This circuit does not use external power. But used part of the input signal into a power supply. To reduce size of the signal.
A part of the input signal is rectified by the D1 and D2, To charge the C1 and C2. This voltage is also used as a control voltage to the small signal attenuation diode.
The R3, R5, R6, D3 and D4. Which is diode work during non-linearity of the forward bias. At lower input signal to the output signal with low attenuation.
But if the input voltage level is high, will have some voltage is rectified by D1 and D2 to charge to C1 and C2.
The control current will flow up to diode and its dynamic resistances will be reduced to cause output signal is lower.
Figure 1 Dynamic Compressors circuit using power supply from input signal.
Period of operation of the circuit depending on the time constant of C1 of C2, R2 and output impedance of circuit should at a minimum. And During the downtime of reducing the size of the signal can be changed by adjusting P1.
The input impedance of circuit should have a highest input impedance.
The diodes for this circuit, Should be a germanium because has threshold of forward bias lower and the graph of the function flatter than silicon. The graph in Figure 2 shows the response of the circuit. By using diode germanium and silicone.
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