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Re: Solid State Control of Neon Lights....
As promised - the rest of my previously brief message:
Basically, a triac is what you are looking for. And the ideal interface is
through optocoupling. That said, there's a number of approaches from here.
A triac is triggered by low voltage dc (3v and up) and this allows higher ac
voltage (120v-230V) to flow as long as the trigger is held high. A primary
problem is that the constantly changing current in the conventional neon
transformer causes inductive currents to flow out of phase and these
currents not only add to the overall current but they can also prevent the
triac from shutting off. Solutions to this problem range from series
capacitors that in essence 'drain' this current, a method I don't favor - to
designing the circuit for a wider crossover point. That is, the triac shuts
off at +4 and -4 Volts rather than 0. This can be accomplished in a number
of ways. Turning this triac on or off with either an optocoupler or your
own led/photosensor combination is relatively straight forward if you have a
basic knowledge of electronics. Autodimming is considerable trickier. I
use a neonics dimmer where I disect the potentiometer and replace it with a
variable light source & sensor.
Lately, as I am designing eeprom chip driven circuits for all types of
complex effects, I've migrated over to P& B high current optocouplers. They
are sturdy and their 40W rating seems to eliminate just about all of the
other messy stuff. It's not correct theoretically, but I've had no failures
over the past three years in both indoor and outdoor applications.
And there _are_ of course solid state neon controllers on the market at a
reasonable price. Rocox has perhaps gotten better? The early ones really
sucked..
Promo plug - the eeprom controlled circuit I design is a low cost user
programmable controller - for further details feel free to contact me.
Kenny
> Does anyone know of a circuit using semiconductor devices to
> control neon lights? Are large neon signs always controlled
> using mechanical relays?
>
> Thanks!
>
> jim thompson
>
>
Kenny Greenberg Neon Artist, Scenic Specialist, Columnist - Internet World
c/o KRYPTON NEON 34-43 Vernon Blvd Long Island City, NY 11106
Ph: 718-728-4450 Fx: 718-728-7206 Email: kenny@neonshop.com
http://www.neonshop.com gopher://gopher.panix.com:70/11/nyart
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