This very complex circuit in terms of the number of transistors was found in Radio Electronics from March 1966. The circuit is for low impedance headphones. The transistors are from the time.
This photoelectric circuit from a 1960 publication uses a 6.3 V electromechanical counter, common at...
We found this circuit in a magazine 73 from the 90's. It is a circuit indicated for radio-amateur...
) This circuit uses two 4046 CMOS PLLs to produce a modulated signal of good intensity. The MOSFET can...