This circuit is from old documentation, using a component that cannot be found easily today. The indicator is a galvanometer, and the input voltage is in the order of 1 V.
This micro AM radio will tune strong stations in the frequency range between 530 and 1,600 kHz....
This unijunction buzzer configuration appears in this section from many publications and sources. The...
This counterphase output step was obtained in a Japanese magazine of 1957, a time when the...