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 alarm, from a 1996 magazine, can be fitted with two BC548s in the original configuration...
Using only one general purpose transistor this circuit is powered by batteries. The lamp of the...
Can be used as a shield, this old American documentation circuit offers digitally selected...