This circuit indicates a digital value through a moving bar. The circuit is TTL and must be powered by 5 V. We find this circuit in a Texas Instruments optoelectronics manual.
This well-known circuit triggers a relay when light striking the phototransistor is cut off. The...
In this circuit the transistor switches when the voltage reaches the pre-set value in the trimpot. The...
This rectangular signal generator was found in an Electronics World of 1966. The transistors are...