This LM380-based circuit was found in documentation from the 1980s. The components are current, and the transistor may be a general-purpose equivalent. Note the use of a medium impedance speaker.
Found in the 1976 Siemens transistors manual, this circuit works with AM or FM IF signals. In the...
Three 4011 NAND gates and two more components - a resistor and a capacitor make this oscillator very...
This photoelectric circuit was found in a 70’s Ferranti's documentation. The circuit uses an...