This circuit is from Motorola documentation, but can be implemented with virtually any phototransistor and any general-purpose transistor. The supply voltage can also be changed.
We found this circuit in a Radio Electronics magazine from December 1969. The circuit uses a...
We found this circuit in a 1991 publication. It is intended for low-impedance microphones,...
This circuit can be used in the car to convert the 12 V from the battery in 6 or 9 V up to 2 A....