This circuit is powered by a voltage of 4.5 V, being common in radios of the 60's. The circuit is from Mullard's transistors reference manual.
This TTL circuit uses LED indicators and must be powered by a voltage of 5 V. The capacitor...
Low power RF transistors such as the BF494 or BF495 and even those in the BC series can oscillate well...
This switched power supply was found in a 70s documentation. The basic components are from that...