Matching antenna (CB7458E)

The coil and sockets of this circuit found in a QST depend on the frequency band that is intended to be tuned.

Adjustable Mark Space Oscillator (CB15930E)
This low frequency oscillator with an operational amplifier of type 741 has adjustment of the mark...
Transistor test (CB7381E)
This circuit was found in a Popular Electronics from the 90s. Transistors are general purpose...
Latest Single-Wire Serial EEPROM from Microchip Enables Remote Identification
The AT21CS11 memory device offers an extended voltage range to accommodate lithium-ion battery...