# Seeking simple circuit for converting 5vdc to ~15vac

I picked up some sample smart materials because I have a small project that I want to put 'magic glass' on the outside of so to speak.

I picked up a couple of different sample pieces from a couple different sources to try and one came with a AC adapter/converter to drive the 'clearing' of the smart film, the other came with a small battery operated unit.

Either one seems to clear the material, but throwing the testors on them produced different results.

The AC version (110vac US plug) seems to output ~17vac @ 60Hz. It also seems to clear the film a little better. The DC version (two AA batteries at 3VDC) outputs ~7.5vac @ 500Hz.

I'm not sure if this smart film needs specific frequencies or not, but this was a purchase off banggood of just a couple small sample pieces about 10cmx15cm each.

My project uses primarily 5vdc with access to low-current 3.3v sources. But I'm guessing this thing would draw too much current (for my 3.3v using the existing driver board) to clear all four panes even after I cut them down to fit inside the project.

So I'm guessing I need something that will generate an AC voltage in the 15v range somewhere between 50-500Hz to drive this thing but I know nothing about building oscillators or inverters. I would also prefer something that could run straight off a 5v source.

(I'm running out of room to put new DiY components. (I'm already stuffing a few props, a servo, a stepper motor, at least 25 LEDs, an i2c PWM board, ultrasonic vaporizor, and a a Raspberry Pi with a ReSpeaker shield a pair of speakers somehow inside of a 10"x6"x6" brass lantern! The smaller/simpler the circuit the better)

Any help is appreciated.

--EDIT 1-- the 110vac which outputs 17vac @ 60Hz is only about 1.4ma The 3VDC which outputs 7.5vac @ 500Hz is 7ma

• Can you measure either the capacitance of the film or the AC current at both 50 Hz and 500 Hz? Please add that information to your original question. – Dwayne Reid Apr 17 '19 at 3:01
• try running the DC version that you have from 5V – Jasen Apr 17 '19 at 3:11
• I recall this diffused film becomes clear with 60Vac at line frequency in < 1 second. , frequency is not critical but draws more power with higher f., – Tony Stewart EE75 Apr 17 '19 at 3:17
• @DwayneReid I think my meter will do current on AC as well as DC but I'll have to rig up something as it requires a through-connection in-line and the wires/connectors are soldered onto this thing. I have extra connectors but no hall-effect non-intrusive testing gear. I'll see if I can rig something up tomorrow to test the current and update the post. – Scott Wood Apr 17 '19 at 4:04
• a royer inverter is simple. finding the right transformer to build one may be more difficult. – Jasen Apr 17 '19 at 4:05