This circuit is from a documentation from the 70s. The circuit uses logic gates of the time, which in many cases were arrays of transistors allowing use as audio amplifiers, as in this case.
This single transistor radio without a power supply was found in documentation from the 1960s. The...
T1 and T2 can be BC557 and T3 a TIP32 for lamps up to 3 A. The supply is made by voltage of 12 V...
This circuit is from the time of the tubes, being indicated to operate with transmitters turning off...