In this circuit the triac conducts when switch S1 is opened. We found it in the October 1987 Radio Electronics magazine. The triac is controlled according to the load.
Circuits similar to this appear elsewhere in this section. The transistors can be BC549 (low...
This circuit indicates when a rain is acidic by monitoring its pH. The circuit is from a 90s RE...
In a microprocessor project (shield) for control applications, a triggered clock can be useful....