This circuit was found in ancient American documentation. It provides a 70 Vpp signal at frequencies up to 100 kHz. Observe the high supply voltage.
This protector was found in an Electronics Now from the 90s. The 250 V transient suppressors are common...
Based on an LM36000 OTA this circuit was found in the July 1988 issue of Radio Electronics...
This circuit only works with incandescent lamps and the frequency is adjusted in the pot,...