An article in Radio Electronics magazine from November 1958 showed the construction of this tube audio oscillator. Note the use of lamps as a stabilizer to obtain better sinusoidal signals.
This Schmitt optical trigger with LDR was found in old documentation. The relay must be sensitive, or an...
We found this circuit in the January 1997 Electronics Now magazine. The triac determines the...
This transmitter uses a small loudespeaker (FTE) as microphone and can send the signals to...