Using a MAX644 this circuit was found in the April 1989 issue of Radio Electronics magazine. The circuit is for a 5 V voltage and 50 mA current output.
This circuit has its application suggested in an alarm system. The circuit is from an old RCA...
Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by modern...
This circuit for voltages up to about 20 V was found in a 90s Popular Electronics. The LED can be...