SpudFiles

Okay so I was taking apart an old hand-held TV that ran off of like 6 AA's. I come across a circuit board with a metal cover that read "CAUTION HIGH VOLT". Malaysian for "Pull me out!!" It also had an interesting glass tube on it which the picture was projected from. I took the two leads off a board and thats it. Hoping there is anyone who knows a little bit more about these things. I think it might be a miniature flyback setup. Pic below.

Detach the lamp, attach two leads where the bulb was attached, secure one wire to a table &c and draw an arc with the other lead, record the length that the arc started.

It could work, though it might only have a ~1mm arc.

Attach wires to where the bulb is and do what now? I want to make sure I get this right, its pretty unique!

The photo is not clear enough to show if that is a cold cathode lamp or a fluorescent. The supply is not designed to handle the current of an air arc. It is designed to start a low pressure arc in the tube. The current is very low and the possibility exists it my produce less than 300 volts, which won't generate a spark in a gap. This is very unlikely to work as an ignition source. The HV warning is to prevent you from getting a nasty jolt. Note, it says Caution, not Danger. This is due to the limited current.

How's your knowledge of electronics, I hope you recorded the make, brand and model number of the TV otherwise you'll have to trace out the circuit.

To help find the working voltage and polarity, look for a large electrolytic capacitor, that will give you the polarity and a defined limit to the maximum voltage it'll run on.

I am going to school for automotive so I have a decent understanding of them. Sorry, I'm using a cell phone and it doesnt get in too close. It is a Casio TV-600. That's about all its says on the box it came in. How large are we talking, like a photocap?

Photocap, maybe larger, I'm think 68 to 220 microfarads, If you have access to a variable PSU, hook it up to that and increase to but not beyond 16VDC.

This turned up after a quick Google, I can't download it, TAFE library is blocking it.

It is the backlighting for the LCD display like tech mentioned.

Not at all useful for an igntion system.


http://www.radiomuseum.org/r/casio_lcd_ ... _tv_6.html

The output of the inverter for the tube is high frequency AC, not DC like a camera flash. The current is limited to regulate the lamp brightness and save battery power. The lower voltage and current limiting for the bulb makes it impractical for an ignition.

i have the same tv and we only have digital tv signal now so its useless, tech you say its high frequency ac could i use it make a portable induction furnace

Interesting thought. Induction furnace with about 1/2 Watt of power. You might get enough heating on a thermometer to see a temperature rise.

So why does the cover say high voltage? I really want to understand the circuit better, I haven't ever came across something like this before. That is definitely it on the link.

I'd disagree that it's useless for ignition, if it's output is HF AC then you can connect a Cockcroft-Walton voltage multiplier

Sorry about the link, it isn't meant to be offensive, I can't link to google searches so this has to do.

Edit: Tech, I'd say that you would have 1/10W induced power in the heated object, I doubt anything would register it.

I like the link.

The multiplier may be able to make it useful. Fast recovery diodes will be needed.

Zeus wrote:Sorry about the link, it isn't meant to be offensive, I can't link to google searches so this has to do.

Why not? It's hardly difficult.

Even if Google is blocked for some reason, the link isn't hard - just http://www.google.com/search?q= with any search terms written after it (using + in place of spaces).

Heck, worst case scenario, right click on the "Redirect link" on the page you linked to and select "Copy Shortcut" (if using IE) or "Copy Link Location" (if using FF), which will give you a link straight to the Google search!

If you use such sites in future (I usually don't, as they can start unpleasantries), I'd recommend the less offensive version of "Let me Google that for you" found at LMGTFY.com