# Can a TRIAC be used to reduce power consumtion for a charger?

## Main Question or Discussion Point

If my understanding of triac's is correct then the triac will conduct current until the amperage flowing though it drops below the threshold. If that is true would adding a triac before the primary induction coil reduce power consumption?

If it did, how would the you reestablish the connection? Would it automatically reestablish itself after a wile, or would the circuit be broken forever?

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After the applied voltage to a triac crosses zero, the triac remains OFF (non-conducting) until it is triggered with a pulse from a (passive) timing circuit. Once the triac is turned ON, it remains ON until the input voltage crosses zero again, which turns the triac OFF.

Delaying the triac turn-on each half-cycle reduces the rms voltage to the charger and reduce power consumption, but the charger may not work correctly due to lack of input voltage.

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It makes sense now
Thanks a ton!

TRIAC's will kick off as soon as the amperage drops below the threshold, so whenever the AC current reverses direction the TRIAC will brake the circuit. This happens about 60 times per second. So using a TRIAC for power conservation is not such a good idea

Most hosehold incandescent lamp dimmer switches are just triacs with a manually adjustable gating circuit. When you adjust the dimmer you are just changing the delay in time between when ac voltage crosses zero and when the gating circuit turns on the forwardly biased half of the triac; the triac is like two inverse parallel SCRs with their gates tied together. It does this for both positive and negative halves of the sine wave. So, turning down a dimmer (increasing the triac gating delay) "conserves power" since less current flows to the lamp filiment for each half alternation. Triacs could easily be used at the power delivery end of an "intelligent", automatic, control system to throttle back resistive loads (water heater elements, resistive heating, incandescent lighting, etc) and thus conserve power. Not paying your electric bill for 3 months in a row is another way :surprised