Current amplifier circuit

摘要

A current amplifier circuit has a first transistor with a collector and a base which are electrically connected, a second transistor connected in series with the first transistor and having a collector and a base which are electrically connected. A third and fourth transistor are connected in series with the collector of the first transistor connected to a base of the third transistor and the collector of the second transistor connected to a base of the fourth transistor through a resistor having a resistance R. The first, second, third and fourth transistors have the same polarity. An amplified output signal current Rxi/RE is obtained from a collector of the third transistor, wherein RE is the emitter resistance of the fourth transistor and i is the input signal applied to the base of the fourth transistor.