We found this circuit with duty cycle adjustment in the May 1988 Radio Electronics magazine. The source must be symmetrical, and the frequency given by R3 and C1.
We found this circuit in a 1976 documentation. The FET can be the BF245 and the bipolar transistor a...
This circuit is the receiver for the CB13997E. The transistor can be the BC548. We also found this...
We found this oscillator in a publication for radio amateurs from the 70s. The circuit generates...