This circuit was found in a 1967 RCA manual. The transistors are of the time. The adjustment is made to read 7.15 V on the charged battery and the charging current is 3.2 A.
This circuit can operate in a 100 dB range with signals of up to 100 MHz frequencies. Similar...
This audio level indication system for microphones was found in Radio Electronics from the 90s....
This circuit was found in a 90’s Electronic Design. The circuit uses components that are still...