| 摘要 |
PROBLEM TO BE SOLVED: To provide an impedance conversion amplifier for receiving a signal with a high input impedance, and outputting a signal with a low output impedance, capable of obtaining the fixed degree of amplification by switching a switchgear while maintaining the functions. SOLUTION: This impedance conversion type amplifier is provided with a resistance 2 for deciding an input impedance, an FET 4 for receiving a signal, a transistor 6 to be turned ON/OFF by an interlocking switchgear 19, a transistor 10 for allowing the source current of the FET 4 to flow, a transistor 20 for outputting a signal, and an FET type arithmetic amplifier 15 constituting a feedback system to be operated so that a difference between a signal transmitted from the emitter side of the transistor 20 through a resistance 18 and a signal connected through a resistance 3 as the compared result of those signals can be offset. Thus, it is possible to reduce an output impedance according to the actions of the FET 4 and the transistor 6 and the transistor 20, and to obtain the fixed degree of amplification according to the rate of the resistance 17 and the resistance 18 to be connected by turning ON the interlocking switchgear 19.
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