EL panel experiments power supply experiment ... for diy compressor

[Analog_Fan]

My Local shop sells EL Panel and i wanna give it a test ... as well as getting the right transistors.
i wanna do a little little side show experiment.

https://www.vanallesenmeer.nl/EL-Panel-10cm-x-10cm-EL-Sheet

• Afmeting: 10 cm x 10 cm
• Dikte: 0,4 mm - 1,0 mm
• Bedrijfsspanning: 100 V ~ 220 V Optimaal: 120 V
• Bedrijfsfrequentie: 50 Hz ~ 5000 Hz Optimaal: 1500 Hz - 2000 Hz
• Statische capaciteit: 6 nf / m (20 ° C, de RV <80%)
• Helderheid: 30 cd / m2 ~ 126 cd / m2 (bij 120 V, 200 Hz ~ 2000 Hz)
• Vermogen: 108 mw m ~ 1032 mw / m (bij 120 V, 200 Hz ~ 2000 Hz)
• Levensduur: ongeveer 8000 uur
• Bedrijfstemperatuur / vochtigheid: -10 ° C ~ + 60 ° C / RH <90%
• Opslagtemperatuur / vochtigheid: -10 ° C ~ + 60 ° C / RH <65%

probably the same material as used in the T4 opto cells.
a copper plate coated with phosphor.

i have already build a Tube based PSU last week ... albeit, just using wires.
220V in to 15V and back to 200V, 2 equal type/model transformers.

if i rectify it, it will be in the neighborhood of 280/285V DC.

How do i step down to be close to the required 120V for the EL panel sold locally.
a power supply, like YouTuber: RSD Academy is building in of his tutorials?
using a few resistors, capacitors and a transistors and what type of transistor?
Would that be 1 watt or 2 watt resistors? but i don't know the power usage of the panel.
Could someone help me with the math?

so i can pulse the EL panel with a transistor (from an synthesizer eurorack module 10 V.p.p. signal) and what type of transistor resists 120V switching?
to experiments with the EL panel. darlington?

 

[shabtek]

la3a iirc uses an autoformer to step up ac signal and make light flicker

 

[shabtek]

also panel won't respond linearly to frequency sweep so some kind of eq/shaping might be helpful

you can damage panel if it goes too bright

 

[Analog_Fan]

la3a iirc uses an autoformer to step up ac signal and make light flicker

Ya, i wanted to avoid this transformer ... hard to get parts.

i toughed a certain type of transistor + capacitor could do the job aswel.
also in the LA3A the EL panel taps behind the rectifier, but the transformer will give it some AC characteristics, right?

 

[Analog_Fan]

also panel won't respond linearly to frequency sweep so some kind of eq/shaping might be helpful

you can damage panel if it goes too bright

This is what i have drawn is what i had in mind .. for a transplant into the LA-A3.
the usual stuff, accept and extra 470nF at the input.

but don't know which transistor would/could apply for the job.
i have seen some with a collector emitter voltage of 160V.
is that the max operating window?

i already have the transformer setup, 2 equal type/model/brand 15V AC transformers for PCB's.
... and 2 BY164 matching rectifiers.

... and a suitable transistor to power + capacitor for the Panel, a darling ton? ... so it can be powered by line level audio.

 

[CJ]

la3a iirc uses an autoformer to step up ac signal and make light flicker

 

[CJ]

Longevity of the panel must be good, a panel used for a Chinese alarm clock that only glows when somebody hits the light bar is built yo last a few hours, where as the panels from LSI which are made for military fighter jet cockpit lighting will tend to be more robust which is why they used to cost 37 dollars when i was buying them. Also, the wavelength and other specs are very specific.

 

[CJ]

IG you search groupdiy for "T4b Docs" you will find some stuff

 

[shabtek]

El panel wants to be driven by AC, no dc
Try 24 volt transformer in reverse. Drive secondary with audio and connect el to primary might need a strong amp, something that can drive small speakers or +4 line level

 

[abbey road d enfer]

EL panels need AC, not DC.
They are supposed to be driven via a significant resistance; if not, they short the power source. A current-limiting resistor is needed.
You need a small audio amp and a step-up transformer. Let's say you have an amp that delivers 1W into 8 ohms, that's 2.8Vrms, you need to step this up to about 120V. That means a 1:42 step-up xfmr.
That could be a small 220V/5V xfmr wired in reverse. The intrinsic DC resistance of the windings would probably be enough to limit current.
With an amp rated at 10W/8 ohms (ca. 9V rms), you could use 220v/15V xfmr.

 

[PermO]

Some old PA systems used a 100V step up transformer between amp and speakers, could a transformer like that be usefull ?

 

[abbey road d enfer]

Some old PA systems used a 100V step up transformer between amp and speakers, could a transformer like that be usefull ?

It could probably, but anyway experimentation is needed.
So-called "100V" xfmrs usually don't have full LF response, they will lack response below about 50Hz.
100V output xfmrs are usually rated at more than 20W and up to several hundred.
A step-down such as those that are used in the 100V speakers, wired in reverse, could do the trick.
This one is interesting.
https://www.visaton.de/en/products/public-address/accessories/tr-68It has a 4/8 ohms winding on one side and 1.7, 3.3 and 6.7k on the other side.
The 1:40 ratio can be achieved by using the 4 ohms tap driven by the amp and the 6.7k tap driving the EL panel.

 

[Analog_Fan]

I'm gonna try a 220V to 9V transformer (that's what i got laying around here) in reverse in a bit ... and a 2SC945 transistor and put a Eurorack VCO on it.
that's what i came up with last night.

I'm not really a pro on a (audio) transformers.

 

[abbey road d enfer]

I'm gonna try a 220V to 9V transformer (that's what i got laying around here) in reverse in a bit ... and a 2SC945 transistor and put a Eurorack VCO on it.
that's what i came up with last night.

I very much doubt you get anything to work. This transistor is a low power type. What circuit do you intend to use?

 

[JohnRoberts]

70V and 100V AC are nominal audio output levels for fixed install, constant voltage, background music systems.

Indeed such transformers are generally undersized for low distortion operation at very LF.

I recall making these 70/100v output amps down to 5W or less power points.

JR

 

[Analog_Fan]

El panel wants to be driven by AC, no dc
Try 24 volt transformer in reverse. Drive secondary with audio and connect el to primary might need a strong amp, something that can drive small speakers or +4 line level

this is what i tried, i figured now, that i might need to connect to the side of the transformer as well to GND.
the 100R is needed otherwise the transistor becomes "hot" or warm, using bigger resistors doesn't work.

i use a eurorack modular synthesizer VCO module, that outputs a 10 V.p.p. sine wave.

i never got something that resembles a sine wave, but it produces a wave form(something like a modulated base wave form) to probably over 225Volt, having the scope in 50V/ division setting and covering more than 4 divisions
Also at the estimated frequencies of >3k5, it's like a 225V signal, but turning the VCO lower frequencies the amplitudes decreases and pretty fast. at an estimated 750hz there is barely any left.

i tried with my phone and a headphone signal, but than i need to set the scope on 2V/division setting to barely see something move.

looks like that didn't cut the mustard.

 

[JohnRoberts]

That's about half of an ac amp design... missing negative drive, input bias, etc....

maybe look at typical designs and find one to copy as a starting point.

JR

 

[Brian Roth]

Many years ago, I tinkered with EL panels with the idea of making my own version of a LA2 or LA3.

I bought a few different varieties of "night lights" from Walmart and elsewhere. These were thin rectangular molded plastic with a window on the front for the EL panel, and two brass prongs on the rear intended to plug in directly to an standard household Edison receptacle. They were designed for 24/7 usage and put off a soft green glow. I recall they sold for a few dollars each.

As I was typing this, I vaguely recalled all that project stuff was in a box in my shop's closet. Eureka!

One of the night lights was a General Electric "Limelite" night light. Another one in the box was had "Indiglo" molded into the front of the plastic. One package had this URL:

https://www.limelite.com/
Most had "Austin Innovations, Inc." and patent number 5662408 molded into the plastic on the back. I have one, still in the blister pack, from "E.I Products" in Maxwell, TX and and the same patent number.

ANYWAY, I sliced one open with my Dremel tool and extracted the EL panel. I see that I strapped it to a perfboard and had a pair of (unknown) photoresistors ziptied onto the face of the EL panel.

Also in my stash was a small PCB with a LM1875 "5-legged" power amp; I'm not sure where I got that from.

Also in the stash were two Speco brand (model T7010) transformers sold to attach to speakers in a 70 Volt distributed PA system. I had bought those from a local electronics distributor.

In my testing, I connected either the 8 or 4 Ohm "secondary" to the small power amp card, and then used one of the five "primary" taps....probably the one marked for 10 Watts, since that would be the greatest step-up ratio. Using the xfmr "in reverse" from the intended purpose.

It was probably 20+ years ago, but I distinctly recall feeding that little power amp with my bench oscillator. At 60 Hz, I got that soft green glow from the panel. But, as I increased the frequency (same level from the oscillator) , it got brighter and brighter and the color morphed to a bright blue!

Anyway, probably TMI, but might be of interest to an experimenter.

Bri

 

[Fuzzie]

interesting topic...
i did some el related research and art in the past but the talk about it is hard to find ...
i was reading patents from the '50ies about tinoxide transparent conductive layers on airplane windows as a means to defrost them when powerd by a bus bar to help my project futher (at 3 a.m. ofcouse) It is the same principle as the top conductive layer of el panels.. it has to conduct but it also has to pass thru the light comming from the phosfor in the layer beneath it energized by the field between the copper base electrode and the transparent conductor toplayer. In that way it is in fact a light emitting capacitor (LEC

but to not carry away too much,
i dived a bit in my bookmarks and found this :
sound activated el driver

maybe they will share the circuit ?
(or just buy the thing and be done but that would defeat the purpose of this forum i guess)

if any experts here on conductive transparant coatings diy, i'd really enjoy a conversation about that .

my goal with the past project was to develop a way to layer ceramic glazes with the properties of an el panel to make a ceramic vase or piece of art light up. ( i'm a potter)

the transparent conductive coating was where the project sort of stranded, although i managed to get some sprinkles of blue light from a test tile at some point.


hope this in not to much offtopic

 

[Analog_Fan]

maybe they will share the circuit ?

i mailed them.
Hopefully they are willing to reveal the secret.

my Local shop meantioned in the first post that they sell some USB powered boostconverter to power that 10CM x 10CM EL panel, but didn't read in to that.