Found in American documentation from the 1980s, this circuit has a diode feedback. At the exit we have an indicator LED. The LM3900 is a transconductance operational amplifier.
Found in a 1967 Ferranti documentation, this circuit uses a LDR from that time as a sensor....
This low-pass filter was found in an American publication from the 80's. The circuit uses an...
Who is the fastest? This circuit with neon lamp is powered directly by the network (there is no...