We found this TTL circuit in a Texas Instruments optoelectronics manual. The power is 5 V and the LEDs are common.
This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response...
This simple calibration circuit consists of a crystal oscillator that generates an accurate 100 kHz...
This circuit from a Radio Electronics from December 1974 was used in color televisions of the...