IN-9 with pulse wave power supply

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https://youtu.be/mwD-WWELFqY

With DC high voltage power supply, the plasma didn't anchor to the bottom. With 50Hz square wave pulse current, the tube worked correctly.

There are many advantages with pulse power supply: 

1. Saving energy

2. Stabilizing the plasma 

3. Reducing heat emission

4. Preventing cathode poisoning

[gregebert]

The only way I got my IN-9 to behave rationally was to use a current-controlled power supply.

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Thank you for your reply.

Of course I used a current-controlled power supply. In addition to it, I added a 555 timer to trim the continuous current into 50 Hz square wave pulse current.

gregebert於 2017年4月29日星期六 UTC+8下午12時57分44秒寫道：

[Alex]

Indeed, I found they worked far better with un-smoothed 50Hz rectified current limited mains from a variac - putting a cap after the rectifier so they had smooth(er) DC made them unreliable. 

Nice to know this also works with square wave pulsed DC.

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Hi, Alex.

To be honest, I stolen the “pulse wave power supply” idea from you. 

I have some few IN-9 tube with defects, even after burning-in for hours, they didn't recover. 

So I started to google on the internet and found your post that the tube will work with pulse sin wave.

Thank you :)

Alex於 2017年4月29日星期六 UTC+8下午4時21分05秒寫道：

[gregebert]

I think the reason why pulsed operation makes IN-9's work better is because when the tube goes wacky, such as lighting from the other end, etc, the tube is turned-off in the next cycle, then restarts.

It's a lot like Microsoft windoze: Crashes often, for no apparent reason, then is fine for awhile after rebooting. In my house, we call it "flushing the toilet"

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In my opinion, the plasma always ignited from the bottom,because the gap there is smallest. After ignition, the plasma slide along the cathode to the portion with lowest resistance. Sorry for my pool English. I think you can understand me.

gregebert於 2017年4月29日星期六 UTC+8下午11時12分55秒寫道：

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I use two MPSA42 in parallel to replace the MJE340 transistor.

If only use one MPSA42, the transistor become hot quickly. So I decide to use two of them.