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Hi

I have continued to play with variable speed spinners. I wasn't ready to try an all valve (tube) spinner so I allowed myself the "luxury" of two 1N4007 rectifiers to make a voltage doubler from 230VAC. Since I was intending to use a GTE175M as the relaxation oscillator and dekatron driver the doubler gave me 475V for the dekatron and -100V for the keep alive electrode. I have used some jumper blocks to allow the spin to be reversed and to select a number of RC combinations for the oscillator to give a wide frequency range.

Some simple information is here:



When I get a chance I will add some words and a video of the OG4 and GTE175M in action. But I need to install it into a (safe) case first.

Cheers Grahame
Highlands Scotland
www.sgitheach.plus.net

And still another one:



It can also be found in the groups File section:

Files > Nuts & Bolts > Dekatron Apps > Variable Speed Spinners

File: Spinner_Relax_Osc_DC.gif

$17.50 and $2.31 shipping @$19.31 prob solved ...how did that happen ?
Well there s a price war going on right now between Taylor electronic services and loveable mike from three neurons
Taylor go for $13 and shipping (but they might be less at his web site ??)and are made in the 1000'S
mike makes his by hand I am sure by candle light and buys parts at the swap meet , typically in the 500,s for Penney ..watch .3=$5 he did this last week ,surplus part right into the next design,keeps the price the same .

And still another one:



It can also be found in the groups File section:

Files > Nuts & Bolts > Dekatron Apps > Variable Speed Spinners

File: Spinner_Relax_Osc_DC.gif
------------------------------------

Intresting, Mike!

[540V] voltage that value absulutely necessary ?
I calculaterd I need a transformer that has a secondary
os 385V.

eric

No its not. It just happens that 540V is 3x 180V, and easily extracted out of a common nixie supply, without using too many extra parts.

A neon dekatron needs at least 380V to strike, and then the voltage drops to ~200V, maintaining. 450V seems to be favorite value used in old circuits. It gives you extra head room, if the cathodes are connected thru resistors, to gnd. If you look at the schematic, I bias all the cathodes ~80V above gnd. Then my minimum required supply goes to 460V. 500V would be safe, but 540V is still okay. If you look at the old Philips datasheet on the Z504S, the supply can be as high as 1000V.

Why do I bias the cathodes to +80V ? That way the guide drive which idles at 120V, and pulses down to 0V (gnd), looks like +40V idle, and -80V pulsed, as the dekatron sees it. Remember this is the old cathode bias trick used by tube designers for forever. It saves me a capacitor. 80V is also just below the strike voltage of most common neon bulbs (NE-2, INS-1).

It also just happens that I have power supplies that make both +180V & +540V, for sale, on eBay.

[edited by A.J. - please trim quoted material]

"Tidak Ada" <offline@...> wrote:

And still another one:



Files > Nuts & Bolts > Dekatron Apps > Variable Speed Spinners

File: Spinner_Relax_Osc_DC.gif

Thanks Mike, that make s sense!
I am so much focused in using old technology that I did not consider
switching supplies.
Also only voltage doubling instead of muliplication.

eric

At the risk of reducing sales of my supply, you can extract the requisite voltages, from household AC:



From 120VAC, you can get both 165V & ~500V. 120V is the RMS value. It has a peak value of 165V, and the circuit shown, multiplies the peak-to-peak value (330V) by 1.5x, to get ~500V.

For the 220V world, the peak-to-peak voltage is ~650V. This circuit also generates a separate 330V (peak), so you don't have to make an extra hot (literally) divider, and use 350V rate caps which are both common and cheap. The values of the spinner are modified a bit, here, to accommodate the shifted voltages.

Here's a little video, showing the circuit running:



Its actually the jig I use to test the supplies. BTW, relisted, if tapping directly to the AC lines makes you squeamish.