This circuit converts BCD inputs to analog voltages. The operational amplifier must be powered according to the desired output voltage range. The circuit is from documentation from the 90s.
This circuit is from 1964 documentation but can be easily implemented based on current components....
This low-power circuit for small lamps according to transistors was found in the January 1959...
We found this circuit in a 1986 documentation. It is based on TTL integrated circuits that can be...