This circuit was found in Motorola's 1968 documentation. The SCRs are then replaceable with current equivalents. The lamp is 24 V according to the power supply.
The frequency of this circuit depends on C1 and, for the indicated values, it is 1 kHz. Equivalent...
This configuration with the LM383 appears elsewhere on this site. The circuit shown was obtained...
This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time...