We found this circuit in the December 1998 issue of Electronics Now magazine. RF transistors such as the BF494 or BF495 can be used. The circuit works at lower frequencies.
We can use the circuit shown below, obtained from a 1992 documentation. To turn a low impedance phone...
High-brightness LEDs of various colors and even white can be obtained easily in specialized...
This circuit is from an American publication about old neon lamps. The circuit is leak proof and...