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

  • Context: Undergrad 
  • Thread starter Thread starter U4edot
  • Start date Start date
  • Tags Tags
    Charger Power
Click For Summary

Discussion Overview

The discussion revolves around the potential use of TRIACs to reduce power consumption in chargers. Participants explore the operational principles of TRIACs and their implications for power delivery in AC circuits, particularly in relation to chargers and other resistive loads.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that a TRIAC could reduce power consumption by conducting current until the amperage drops below a threshold, questioning how the connection would be reestablished.
  • Another participant explains that a TRIAC remains OFF until triggered and that delaying the TRIAC turn-on can reduce rms voltage to the charger, potentially affecting its operation.
  • A different participant argues that using a TRIAC for power conservation may not be effective due to its operation at the zero-crossing point of AC current, which could disrupt the circuit frequently.
  • One participant describes the function of TRIACs in household dimmer switches, noting that they can throttle back resistive loads and thus conserve power, while also making a humorous remark about not paying electric bills.

Areas of Agreement / Disagreement

Participants express differing views on the effectiveness of using TRIACs for power reduction in chargers. Some acknowledge potential benefits while others raise concerns about operational limitations and effectiveness.

Contextual Notes

There are unresolved questions regarding the practical implementation of TRIACs in chargers, including assumptions about their behavior in AC circuits and the impact on charger functionality.

U4edot
Messages
26
Reaction score
0
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?

Help please
 
Physics news on Phys.org
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.
 
Last edited:
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
 

Similar threads

Replies
4
Views
7K
Replies
8
Views
4K
Replies
12
Views
3K
Replies
9
Views
4K
  • · Replies 359 ·
12
Replies
359
Views
33K
  • · Replies 39 ·
2
Replies
39
Views
16K
  • · Replies 17 ·
Replies
17
Views
12K
Replies
2
Views
5K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
7K