This circuit was found in a Popular Electronics from the 90s. The circuit uses TTL technology and must be powered by a voltage of 5V.
This circuit can be powered by 2 or 3 small batteries. The resistor can have values between 220...
Found in 90s Popular Electronics, this circuit produces a modulated infrared beam for a remote...
Found in General Electric documentation from the 1980s, this high speed perforated tape reader...