This common dimmer configuration is one of thousands that have appeared in electronics publications around the world. This one with a triac was found in October 1977 Radio Electronics magazine.
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...