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help finding proper transistor

conductor3

Jun 7, 2011
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i need to find a transistor that can conduct 110 volts (dc converted with NTE5322W bridge rectifier) across the emitter and collector and can be turned on with 5 volts (microcontroller voltage) on the base i dont care if its npn or pnp i dont mind throughing in a couple 4049s
to change the positive to a negitive
thank you




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- kevin
 

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For safety, have you considered a solid state relay?
 

conductor3

Jun 7, 2011
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the thing is i cant find an ssr with a high enough rateing and high frequency (pwm)

if you can find one that can do that and is afordable let me know it wold be very helpfull the most i found were 60 volts half of what i need for my christmas lights set up its going to be fun this year i need 19 of them so 5 bucks possibly maby 6

thank you

would this work
http://www.ebay.com/itm/Solid-State...333?pt=LH_DefaultDomain_0&hash=item461034a52d
 
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the thing is i cant find an ssr with a high enough rateing and high frequency (pwm)

You'll need t tell us what rating is required before we can help you.

would this work

We can't tell. See above.

What are you switching?

What voltage does it run at?

What current does it draw?

It is possible that even if that SSR was appropriate, it might need a heatsink.
 
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conductor3

Jun 7, 2011
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up to 2 ampers at 110 volts dc

im switching christmas lights

i just need to be able to do what a common transistor does only with a much higher voltage and up to 2 amps using 5 volts to turn the lights on off using pwm for dimming

and actualy the most im going to run is 3 strands (150 ct) on one relay
 
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Yes, that solid state relay should be fine and it should not require heatsinking.

edit: and a transistor can't do this because you're switching AC
 

conductor3

Jun 7, 2011
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heres a quick scetch (not final)

im using a bridge rectifier to convert to dc
i do see how it got all mixed up im not very good with social skills
thank you:)

edit: im going to through in fuses to so i dont burn down my parents house ;)
 

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conductor3

Jun 7, 2011
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o and so it doesnt confuse any one im ueing an arduino with vixen software to do a music show so i cant just get a simple dimmer to do it for me becouse its dmx but i dont need any help with this its already set up and sending pwm to leds i just need help with the ssr portion of this project to dofull scale with incondesonts
thanks:)
 
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(*steve*)

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What's the bridge rectifier for?

I presume the lights run from AC.
 

conductor3

Jun 7, 2011
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yes they do,but if i were using ac i would need to do zero cross detection to be able to dim wth pwm which is what im going for (to much money for me)
but dc doesnt need zero cross detection (becouse it never alternates) making it much more simple to dim with pwm thats why im doing it that way
and i remember when i was ten i would hook up a ton of 9 volts to a strand of lights and they would turn on i had 12 of them (108 volts) and it was dc so i know it will turn on with dc too

im thirteen by the way so bear with me
ive been doing diy projects since i was 6 and c# programing (microcontrollers mainly) since i was 9 years old so im pretty famillier with this stuff (not all of it but allot) im also haveing my dad help me but i need togather all the info first before we start building it
 
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I would advise you to use AC. I would recommend you DON'T do mains wiring though.
 

conductor3

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i know thats why my dads helping me

the only thing i need to know is if it will work with pwm to dim with the circuit i posted and the ssr is a dc ssr
 
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i know thats why my dads helping me

Good. :)

Is he reading this too?

the only thing i need to know is if it will work with pwm to dim with the circuit i posted and the ssr is a dc ssr

A AC only SSR is often controlled by a triac. This will only turn off at the end of each half cycle.

A DC SSR is typically for AC or DC and uses mosfets to switch the incoming power asynchronously of the mains waveform.

Zero crossing is something else again. It determines when the relay switches on.

Skipping the rectifier saves you some mains wiring, and the less of that there is, the better.

If you have some boxes with mains sockets on the outside switched by the SSRs inside the box, and the (well isolated) connections to the low voltage side of the SSRs coming out as a separate cable then you can be far more certain that you are not going to come into contact with the mains.

The other advantage is that you have a general purpose interface box which will allow you to control other AC equipment.

It would be advantageous to use an insulated, sealed box, and to keep the mains and low voltage wiring as far apart as possible. Any exposed mains connections should be covered with heatshrink tubing or use shrouded spade connectors, etc.
 

conductor3

Jun 7, 2011
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yes my dad will be looking a this when he wakes up

and im going to put it al in a water proof enclouser

thank you for the help

ill private mesage you once the parts arive and my dad and i put t together
 
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conductor3

Jun 7, 2011
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A DC SSR is typically for AC or DC and uses mosfets to switch the incoming power asynchronously of the mains waveform.

what does asynchronously mean
 

conductor3

Jun 7, 2011
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o and some other questions
so i will be able to hook up mains directly to a dc ssr?
will a dc ssr (the one i shoed you)sitch mains fast enough to dim the lights using pwm from an arduino?
will an ssr (blown)that has opto isolation built in harm my arduino?
 
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(*steve*)

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what does asynchronously mean

It means that the timing is not dependant or synchronised with anything on the incoming waveform. That is required for PWM.
 

(*steve*)

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so i will be able to hook up mains directly to a dc ssr?

Yes. You'll note that the SSR is actually described as both AC and DC (albeit, not really well)

will a dc ssr (the one i shoed you)sitch mains fast enough to dim the lights using pwm from an arduino?
I believe that this should not be an issue. The issue is more likely to be one of generating interference.

will an ssr (blown)that has opto isolation built in harm my arduino?

VERY good question!

The answer is that the isolation is provided in such a way that even if you destroy the switching element, the isolation is preserved.

Of course, nothing is ever 100% reliable, but for a good quality part, this is true,
 

conductor3

Jun 7, 2011
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It means that the timing is not dependant or synchronised with anything on the incoming waveform. That is required for PWM.
so if i use dc so there is no waveform to sync to (it's just a steady voltage) would i still be able to use pwm like i do when powering my leds with transistors

the only reason i ask is becouse im useing both ac and dc loads (different circuits useing 2 seperate ssrs)
 
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(*steve*)

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Yes, an SSR designed for AC or DC can be used for both...
 
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