We found this circuit in a 1976 publication. The transistors can be BC547 or 2N2222. Crystals up to a few tens of Megahertz can be tested. The LED can be of any type. The capacitors must all be ceramic.
This 1967 Motorola circuit is intended for operation with signals up to 250 MHz delivering a 50 MHz...
This dual operational circuit of the time was found in an American 1980s documentation. The...
This circuit was obtained from an old American publication. Transistors are germanium types of the...