electroluminescent panels, lightboxes, and banding issues

[h0ughy (David)]

Originally Posted by troypiggo

Thanks mate. I have made a lightbox to hold the panel in place. Difference with mine is it is flat, so doesn't have the diffusion that yours does, so the banding is noticeable. Yours may well be gettingi the banding, but it doesn't matter because of the diffusion. I wanted something flat for easier packing. I'm thinking I might make a foldable one.

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well the box it is in is only 4cm high - so if that isnt flat enough for you you are hard to please? yes i had the banding - thats why i put it in the box with the drafting film - its the only way you will remove it

[wasyoungonce (Brendan)]

Originally Posted by troypiggo

Sorry guys. The power supply has "DC Regulated Power Supply" on it. Doesn't that mean it's a regulated power supply?

Well yes it's regulated in that it regulates an output voltage but it's/they are not good at producing an output with low "Hum" or "Noise" levels.

Even Step down transformer PSUs can have hum & noise but switch-modes are more susceptible to creating noise on their outputs. It's due to the they way they "switch" a high DC voltage (at high frequencies...15- 30Khz) to produce pseudo AC...which is in turn rectified, regulated & filtered to produce an output voltage.

Switchmodes are used because they are more efficient, size is smaller & use less copper.

Good or well designed switchmodes are very good & efficient bad ones or badly produced ones are Ok for general work..but not for sensitive equipment.

As I said I have a version of that PSU my self...and it creates noise. So I adapted a computer PSU as a 12VDC supply (for my mount supply). Sure it's a switchmode as well but in general these are very well designed & create less output noise. It's ok for my equipment ATM.

Soon...in the future I'll be building my own step-down transformer DC regulated supply for the mount & other equipment. I prefer them as it's much easier to produce a nice "clean" output.

Not many step-down transformers PSUs are available now days...pity!

[troypiggo (Troy)]

Originally Posted by h0ughy

well the box it is in is only 4cm high - so if that isnt flat enough for you you are hard to please? yes i had the banding - thats why i put it in the box with the drafting film - its the only way you will remove it

Have you been talking to my wife?

Originally Posted by wasyoungonce

Well yes it's regulated in that it regulates an output voltage but it's/they are not good at producing an output with low "Hum" or "Noise" levels.

Even Step down transformer PSUs can have hum & noise but switch-modes are more susceptible to creating noise on their outputs. It's due to the they way they "switch" a high DC voltage (at high frequencies...15- 30Khz) to produce pseudo AC...which is in turn rectified, regulated & filtered to produce an output voltage.

Switchmodes are used because they are more efficient, size is smaller & use less copper.

Good or well designed switchmodes are very good & efficient bad ones or badly produced ones are Ok for general work..but not for sensitive equipment.

As I said I have a version of that PSU my self...and it creates noise. So I adapted a computer PSU as a 12VDC supply (for my mount supply). Sure it's a switchmode as well but in general these are very well designed & create less output noise. It's ok for my equipment ATM.

Soon...in the future I'll be building my own step-down transformer DC regulated supply for the mount & other equipment. I prefer them as it's much easier to produce a nice "clean" output.

Not many step-down transformers PSUs are available now days...pity!

Thanks for putting up with all my questions. What about those ferrite rings - how many, where?

[wasyoungonce (Brendan)]

Originally Posted by troypiggo

Thanks for putting up with all my questions. What about those ferrite rings - how many, where?

no problems...easiest thing to try is to just put one ferrite bead on the cord running to the device (either the +ve or -ve lead). Loop the cord thru the ring once...and out to the device (if you can).

Or try one of the other Jaycar ferrite chokes.

Problem is your trying to fix a design that may be uneconomic to do so.

[netwolf]

The refrence to "light" earlier is to the Weight of the power supply. The switchmodes are usually very light weight.

I would also be interesting in getting a non-switchmode regulated 12V unit with enough amps to power a scopes and accesories. If someone knows one please link to it.

Regards
Fahim

[mswhin63 (Malcolm)]

Mains hum is on many occasions a bit of a problem and requires significant filtering to reduce or eliminate the problem. Ferrite bead and inductive filter is more designed for High Freq filter where as large capacitors are design primarily for low freq filtering. Combination provide bandpass or bandstop filtering.

Batteres are one very big capacitors. It is possible that the regulated PSU has not got enough filtering for EL lighting cct's.