The circuit shown is from the 1977 GE semiconductor manual. More modern equivalent SCRs can be used. R1 must be wire type.
This circuit was found in a Radio Electronics of August 1952. The transistors are germanium types...
The purpose of this circuit is to add millivolt scales to a common multimeter. Used transistors are...
Found in an English documentation, this siren of good power is indicated for several applications, based on...