This circuit was found in 80's documentation from Analog Devices. The formulas for calculating the components as a function of frequency are given next to the diagram.
Found in an old publication, this is a transmitter with a spark coil. The high frequency...
This circuit was found in a 90s Hands-On Electronics. When a signal appears at the headphone...
In the figure we give a suggestion of a high-power stage to excite a speaker with the 2N3055. The...