Code practice oscillator (T428E)

This circuit was found in a 1938 Radio Handbook. The circuit can be designed based on other triode valves. The high voltage source is not given.

LC Oscillator (CB4552E)
This oscillator can produce 2 to 10 MHz signals depending on the coils used. The transistors can...
Home Security System (CB4804E)
In the figure we have a security system consisting of a sophisticated alarm found in a 90s edition...
15 V x 1 A Power Supply Using the LM723 (CB862E)
The output voltage is adjusted by the trimpot. The power transistor mist be mounted on a heatsink. The 3.9...