We found this micro amplifier in a technical documentation from National Semiconductor. The circuit can be used on an experimental phone, being powered even by alternative power sources.
Used with telephones at the time, this circuit was found in Popular Electronics from the 90s. The...
Unlike the CIR4620 circuit, the circuit shown in the figure operates by capacitance. This means...
This 1 A circuit was found in a Philips documentation from 1966. The transistor is of the time,...