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[SOLVED] PDLC Smart glass power supply

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Dec 11, 2009
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I want to know how to design power supply for PLDC Smart glass ?? . As per speciation sheet they operate on 60V AC, 50 Hz or 100V AC, 60Hz. So power supply available in market are triac based (triac based dimmer) ??? or they use some inverter based circuit?? . Please tell there working principle.

If there is anyone can give any reference schematic then it is very helpful.

The film doesn't draw a lot of power, merely 1 or 2 or 3 Watts.

To start experimenting it ought to be a variable AC source.

The easiest power supply is to step down house voltage. You might get by with capacitive drop, or with a certain amount of resistive drop.

There are power inverter circuits drawing from a 9V battery. Often these involve a transformer which you might need to build yourself. However draining 4W from a 9V battery depletes it rapidly.

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Example, resistive drop might be workable by installing 1 or 2 kilohms (with adequate Watt rating). If you can obtain a rheostat that lets you vary amplitude to load.
resistive drop reduces 120VAC load gets 70VAC 3W.png
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Thank you for replay,
Can I use triac based supply(dimmer, some module available for Adriano, I am familiarly with this ). I am asking this because it is given in specification that it require sine wave. So inverter circuit is necessary or I can use triac based dimmer?? And what exactly used in commercial supply's??



A triac based supply won't output sinewave unless you just use the triac as ON/OFF switch.

But when I read "triac based supply" I imagin the triac does some kind of regulation.


Light dimmers aren't likely to work with smart film. The inexpensive triac kind are intended for incandescent bulbs. Modern compact fluorescent bulbs need a modern different kind of light dimmer. Further research might turn up a dimmer that works with smart film.

An autotransformer is versatile since you can dial in any AC voltage from zero to house voltage plus ten percent. (I paid $10 for a used 1.75 Ampere unit on Ebay.) With your current draw being a few mA, an autoformer is more than adequate.

Two inexpensive wall wart transformers in a row. The first steps down, the second is backwards at a lesser ratio than the first.
Say, 120 VAC to 9 VAC @ 300mA. Then a second one designed to step down 120 VAC to 15 VAC, installed in reverse. The resulting output is 75 VAC, usable for smart film.

What type of circuit used by the power supply (for smart glass) available in market? are they using transformer as you mention ? or something else ?


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