Found in an English publication from the 1980s, this circuit can be built with equivalent transistors such as the BC549. The signal must be applied to an external amplifier.
Found in an old Popular Electronics, the purpose of this circuit is to give a strong discharge in an...
The circuit shown is from the 1993 Motorola Linear Interface ICs. The power source may be common...
Indicated by a Popular Electronics of the 90s originally to measure the light determining the exposure...