This circuit was found in 1980s Radio Electronics. The circuit includes the power supply. The ICL8038 circuit was very common at the time in this type of application.
September 2017 - Digi International's SX 868 RF modules for low-power 868 MHz CE / RED operation...
This circuit is from an 80's technical newsletter. The circuit can use any general purpose...
Found in a 1990 PE Hobbyst, this 4-digit circuit has a high response speed. The circuit is based...