WATER_LEVEL_SENSOR_AND_CONTROL

Published:2009/7/6 9:20:00 Author:May | From:SeekIC

When the water level is low, the probe is out of the water and SCR1 is triggered on. It conducts and imposes a heavy load on transformer T1's secondary winding. That load is reflected back into the primary, gating triac TR1 on, which energizes the load. If the load is an electric valve in the water-supply line, it will open and remain open until the water rises and touches the probe; this shorts SCR1's gate and cathode, thereby turning off the SCR1, which effectively open-circuits the secondary. That open-circuit condition, when reflected back to the primary winding, removes the triac's trigger signal, thereby turning the water off.



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