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Remote trigger

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raymo

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I have a project that I have started on that involves the turning on of a power source. I plan to use standard 120vac as the power source that will be turned on. my problem is that the signal that i want to use to turn the circuit on is roughly the equilivant of a AA battery (1.5v); I can boost the 1.5v to either 6 or 12v if needed. I thought that I could use a SCR to take care of this but I am not sure if 1, a scr will work, or 2, what kind of scr to use. The idea is to have 120v run through my circuit to power a light which will remain off untill the 1.5v signal trips the circuit and turns it on and stays on after the 1.5v signal fades. Any ideas?

Thanks
 
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In particular, a solid state relay that is designed for 120 VAC. Try googling "solid state relay" and see what turns up.
 
Electronic Goldmine (google them too) has 120-230V 10AMPs solid state relays for a fair price.. Input was 3+ volts DC.

I bought 10 at I want to say $4-5 each on my last order.
 
out of curriosity, how can anyone recommend a part without knowing the current requirements?
 
I read low DC volts and 120volts AC out. I too think he is looking for a solid state relay, so I recommened a low cost one that will handle 10AMP. He never stated the current, so I posted what this relay could handle.

But you are right. More details will get him a better solution.
 
As far as current goes, the 120vac that I want as an output needs to have the amperage of a wall socket. In essence I want a small power source to flip a switch and turn on a light that normally would be plugged into a regular wall socket. Hope this helps.
 
raymo said:
the 120vac that I want as an output needs to have the amperage of a wall socket. In essence I want a small power source to flip a switch and turn on a light
An 1800W light?
You will be able to cook yourself with that much power!
A wall socket can supply up to 15A. A light uses less than 1A.
 
lol. welcome to reality. You could find a relay (SS or mechanical) that will switch 15A but you will pay for it. If you want to switch a light, then you can get by with a much more modest device. For example, take a look at dimmers, the consumer ones are rated up to 600 W (about 5A) - controlling more adds needless cost since the vast majority of applications will be no more than 300W..

I suggest you figure out what you want to control and design for at least 50% over the current draw.
 
So if an average light pulls around 1amp then a relay capable of 1 or 1.5 amps should be sufficent, right? The light I am talking about is like an average desk lamp, or something close to that nature, 60w bulb max.
 
So a 1amp circuit would be sufficient to power a 60w or 100w bulb. As far as the relay goes, will it stay on after the initial electrical signal? Simplified, i can get the origional 1.5v to that of 6 or 9v but that only occurs for 3 seconds. I need the relay to latch and stay on and provide the 120vac current to power a desk lamp from the (1.5v, 6v, or 9v dc current) initial 3 second signal. What else do I need besides a relay to accmplish this?
 
You can wire a mechanical two-pole relay to latch itself on. But then you need an electronic circuit to turn it off.
You need a flip-flop circuit and a triac or relay. Then a signal turns on the light and a repeated signal turns it off.
 
At this point, I would move to a TRIAC and use a MOC303x to control it (and bag the relay). the MOC303x datasheet has a pretty complete circuit. Use a flipflop to drive the MOC. switch toggles the FF. debounce the switch. https://www.fairchildsemi.com/ds/MO/MOC3033-M.pdf

obligatory pitch for super cheap uC: a <$1 8 pin micro could do the toggle, debounce and drive the MOC.
 
quick question do the internal batteries on the (Tektroniks 211 oscilloscope) have to be able too hold a charge for the external or A.C power to make it function. I'm guessing they do or I have to keep looking for my lost manual. THANKS FOR INFO DON
 
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