This circuit is used in magnetic tape recorders, having been found in documentation in the 1960s. The circuit uses Japanese transistors, and the critical components are transformers.
This flip-flop using two bipolar transistor was found in a publication of the year 1968. The...
Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by...
This 3-step level indicator uses only passive components. LEDs are common and trimpots can be 4k7...