This circuit triggers a relay when the set temperature is reached. The circuit is from an old documentation. The relay may be equivalent according to the transformer secondary voltage.
This circuit was found in a Popular Electronics from the 90's. The circuit has gained 10 to 20 dB...
This simple circuit uses a car ignition coil. The circuit appeared in the 1983 Radio Electronics Annual...
The modified Hartley oscillator seen in the figure can generate signals ranging from 3 MHz to 10...