This circuit makes use of an optical coupler to isolate the telephone line. The circuit is from 1970s documentation. The components admit equivalents.
This circuit is from an old publication, from 1992, being indicated to test the old joysticks of...
This circuit simulates lightning using a small white lux type fluorescent lamp. The circuit is...
The frequency of this astable multivibrator depends not only on the capacitors, but also on the...