In this circuit, the integrated amplifier used is uncommon today. The circuit is from an American documentation from the 70's making use of a power transistor for output. A TIP32 can be used.
This common emitter amplifier with 43 dB gain was found in the August 1970 issue of Radio...
The diagram below is an application of the Texas Instruments TPS25221 to an ISM controlled power...
In this circuit of a 1968 publication the unijunction may be 2N2646 and the transistor BC548. The...