The transistors of this circuit found in an English 1980s documentation may be the modern BC548 equivalents. The circuit is battery powered and the earphone must be crystal.
Here we show how to add a reset key to the monostable using two NAND gates (CB127E). When the key...
This short circuit protection circuit accelerates the blown fuse in case of an output overcurrent. The...
This signal injector circuit, an astable multivibrator, was found in a 1971 magazine. The circuit can...