This driver for audio signals using the TAA435 integrated circuit was found in Philips 1968 documentation. The integrated circuit is difficult to obtain today.
A flash of light on one sensor or the touch of your fingers on the other type of sensor will turn...
This circuit with only two transistors is from an 80's EDN. It can be implemented with two current...
This high gain small signal amplifier circuit was found in an old publication on transistors....