This circuit is from March 1978 Radio Electronics. The 4-digit circuit uses a period module and is battery powered. The main integrated circuits are CMOS and TLL.
This traditional configuration found in a Radio Shack document can use 2N2646. More keys can be...
This is the circuit of a turntable from the 1970s. We found it in a repair article in the December...
Using the CA3018 released at the time, this circuit was found in the August 1970 Radio Electronics...