VARIABLE ATTENUATOR AND AGC CIRCUIT USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a variable attenuator whose impedance is made constant. SOLUTION: The variable attenuator is provided with a PIN diode 22 whose cathode is connected to a connection point 12 and whose anode is connected to a constant voltage terminal 21 to which a prescribed constant voltage is applied and with a series connection body consisting of a resistor 23 connected between the anode and ground of the PIN diode 22 and a capacitor 24. Thus, the impedance when viewing from a terminal 11 can nearly be equal even when a level at a voltage controlled terminal 19 is varied.