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How can I switch 170 Volts DC from 4017 counter ICs ?

 
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daisy744



Joined: 27 Aug 2004
Posts: 2
Post27 Aug 2004 5:45   How can I switch 170 Volts DC from 4017 counter ICs ?
Hi all

I have built a timing circuit for running a clock. The digits in my clock are Nixie tube display and they require 170 volts to operate. I have built a power supply to provide both 9 volts for the timer and 170 dc for the Nixie tubes.

I am having trouble switching the 170 volts to the tubes. I have used a transister to drive a solid state relay, the transister switches fine but relay does not block the full 170 volts when off. I have about 140 when on and 130 when off. Why does won't the relay turn off !!!!

The relay is 3-32 vdc input and 3A 240 ac for the output.

Can anyone help ?

Adam
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El_Paco



Joined: 07 Mar 2002
Posts: 29
Post27 Aug 2004 8:37   Re: How can I switch 170 Volts DC from 4017 counter ICs ?
at first - i would try it with a optocoupler on the low voltage side.
if you find a optocoupler with high voltage transitors ( i dont know if this exist) you can switch the tube voltage directly.
If not, you should control a high-voltage transistor via the optocoupler.


the answer for your problem is in your question - you have a solidstate for 230 V AC.

in the past the most solide states are optical triggered triacs - some of them has also a integrated zero cross detection circuit.
But you use DC.
Triacs switch off in the zero point.

it give severally ways to switch off a triac - one should be to reverse the voltage.
in the solid state relais, if a triac is integrated, you can try to switch the polarity of the voltage (before this you must turn of the control voltage).

I hope you understand what i mean - i'm not sure - never try this way and i also did'nt know your complete circuit - i also have no experiences with dixie tube.
It's a suggestion - no warranty.
Sorry for my bad english.

best regards
El Paco
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daisy744



Joined: 27 Aug 2004
Posts: 2
Post27 Aug 2004 8:47   Re: How can I switch 170 Volts DC from 4017 counter ICs ?
thanks, i'll give it a try.

ps your english is not that bad !

adam
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pico



Joined: 30 Sep 2001
Posts: 261
Helped: 6
Post27 Aug 2004 8:56   Re: How can I switch 170 Volts DC from 4017 counter ICs ?
Please check the attached schematic.

Sorry, but you need login in to view this attachment
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echo47



Joined: 07 Apr 2002
Posts: 4205
Helped: 565
Post29 Aug 2004 10:32   How can I switch 170 Volts DC from 4017 counter ICs ?
Here's a fun web page, including a "Nixie Clock project" that uses 4017 chips and MPSA42 driver transistors.
http://www.electricstuff.co.uk/

Don't electrocute yourself!
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Kevin Weddle



Joined: 10 Jul 2004
Posts: 101
Location: San Antonio, TX
Post30 Aug 2004 17:41   Re: How can I switch 170 Volts DC from 4017 counter ICs ?
Be clear as to the properties and meaning of your "solid state relay". If your are talking about a thyristor, then generally you will have to turn it on with a high and turn it off with a low. You will most likely need a little more current, so you add a transistor on the logic output. If you are not turning it off then you need a solid ground. Just try grounding the thyristor gate. Then try turning it on with a variable voltage source.
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