R1 may be 10k and R2 100k. The transistor can be the BC548 and instead of the small lamp we can use a series LED with a 1k resistor. D1 is germanium and C1 is 10 nF. C2 can be 47 nF.
We found this circuit in an old documentation for hams. In it we have the way to use a varicap to...
Found in an 80's documentation this circuit uses an integrated from the uncommon era today. Other...
This circuit is stabilized by a thermistor or NTC with a resistance between 2 and 5k. The signal is...