We found this circuit in a 1980s Motorola documentation. The circuit makes use of common operating and the voltage depends on the used type. The components are for a frequency of 500 Hz.
The power supply shown can supply voltages of approximately 0 V to 12 V with a maximum current of 4.5 A,...
This indicator was found in a 1974 publication, but it can be fitted with the BC548 transistor or...
Used with infrared remotes at the time, this circuit was found in a 1991 RE Experimenter Handbook....