This crystal oscillator is indicated for the calibration of IF steps of common radio receivers. The transistor admits equivalent as 2N2222 or BF494. The circuit is from an old American publication.
The critical component of this circuit is the transformer. T1 and T2 can be BD135 and T3 / T4 can...
Found in Popular Electronics from the 90s, this circuit can employ other low power audio...
This circuit is from a 1967 publication. It is possible to power a fluorescent lamp from a 12 V...