Found in old American documentation, this circuit can use crystals between 27.5 and 33 MHz operating on the third harmonic. The transistor admits equivalent.
We found this circuit in an old American publication from the 1980s. Transistors can be...
For those who want to recover an old multimeter of this type, the circuit presented is worth...
This simple low-current charger does not use a transformer, having been found in a 2001...