This circuit is from a 1968 documentation. It makes use of thermistors (NTC) to indicate overheating of charged batteries. Modern equivalent components can be used.
This circuit consists of a voltage regulator for 6 V batteries with a very low voltage drop. The...
This BFO or OFB for listening to SSB (Single Sideband) signals was found in the January 1996 issue...
We found this circuit in a European publication from the 1990s. Transistors are still common types...