This circuit is from a 1966 publication. The frequency depends on the capacitors and on R1 which can have values between 47k and 2.2 M typically. The supply voltage can be between 200 and 300 V.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...