This elementary receiver with a crystal earphone was found in Japanese documentation from the 1960s. The coil has 60 + 40 turns of wire 28 to 32 in a ferrite rod.
This is an integrated clock circuit from the time and was published in the November 173 Radio...
This signal follower was obtained from a Raytheon manual from the 1960s. The transistor is made of...
This oscillator was found in the January 1996 issue of Electronics Now magazine. The frequency is given by...