This circuit is from Texas Instruments documentation from the 1980s. The operatinal ones are from the era and the power supply must be symmetrical.
This is a commercial circuit of a transistor amplifier of some watts with the OC30 transistor. The 12 V...
With this circuit it is possible to excite direct current relays from an alternating signal,...
The reference source for this circuit is a 1968’s Motorola publication. The circuit can be...