This TTL circuit is from a Radio Electronics magazine from November 1983. The circuit drives a set of LEDs. The integrated circuit used is a BCD to decimal decoder.
We found this circuit in a 1990 documentation. The operational amplifiers are type 741 and the LED is...
We found this circuit on an Elektor from the 90s. The frequency is given by capacitor C1. The...
Found in National Semiconductor publication from the 1980s. This gain-100 circuit can be...