This circuit generates signals from 10 Hz to 10 kHz. We found it in a Popular Electronics from the 90's. The components admit equivalents.
This VHF receiver with three transistors and loudspeaker listening was found in European...
This sensor was published in Radio Electronics magazine in April 1962. The two-transistor circuit...
This circuit consists of a monostable multivibrator using the LM3900 transconductance operational...