We found this TTL circuit in a Texas Instruments optoelectronics manual. The power is 5 V and the LEDs are common.
This circuit was found in Philips documentation from 1967. The components are of the time, being...
The Variable Frequency Oscillator (VFO) shown in the figure can generate signals in a frequency...
This circuit uses an operational amplifier to modulate the light emitted by an LED with audio...