This circuit was found in Motorola's 1968 documentation. The SCRs are then replaceable with current equivalents. The lamp is 24 V according to the power supply.
This circuit is one of many that the reader can find in this section for testing crystals. The...
I found this circuit on a December 1976 Radio Elettronica. The Italian magazine no longer exists, but...
June 2017 - Mouser Electronics has in stock the new AC Metallized Polypropylene Film Capacitors...