Found in a 1967 Ferranti documentation, this circuit uses a LDR from that time as a sensor. Transistors can be replaced with modern equivalents.
This is perhaps one of the first capacitive discharge ignition circuits published in a magazine. It...
This circuit was found in old American documentation. It has 40 dB gain between 10 Hz and 10 kHz....
This simple alarm for doors and windows was found in a Japanese publication from the 1960s. The...