We found this TTL circuit in a Texas Instruments optoelectronics manual. The power is 5 V and the LEDs are common.
This circuit can also be used as a simple thermoscope (temperature changes indicator) in the...
This circuit is quite old, from 1964, but can still be mounted with BC558 transistors. The circuit is...
This circuit was found in documentation from the 1980s. The circuit can be implemented with other...