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relay

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yes...there are many devices like that.....one of them is called the TRIAC...( triode AC switch)...used to switch alternating current with a small control current...its solidstate ie no movin parts
 
my voltages would be between 9v and 1.5v dc i need something that will work with that?
i am useing a 555 timer to turn another circuit on and off and i dont want to use a relay bc i tried that once before and the reed relay died in like 5 seconds
 
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Google: "photomos relay"

Ken
 
It would be help if you posted a drawing/schematic of you circuit. It may contain information that would help us answer that. ;)

Ken
 
So, you want a 555 running at 9VDC to switch (like S3) on and off the oscillator powered by 1.5VDC. If that's the case, that photomos relay would not work, 5-8Vdc. The voltage drop across the MOSFET is too high. This one might be more appreciate, with an ON resistance of 0.74Ω:AQV202 Panasonic Electric Works Solid State Relays However, it would be important to know how much current the oscillator draws. I noticed at the end of the link, the author stated that they had no voltage or current measurements. Have you reached a prototyping point where you could measure that?

Ken
 
no, i am waiting because i want to order all the parts at once... is there a more simple way to do this all i am wanting is to be able to pulse the laser with that circuit and also control the frequency of the pulses and the only way i know to do that is with a 555 timer and if i use the 555 i have to run it through a relay
 
If you don't need to isolate the two circuits, you can do as deepak george suggested and use a transistor to switch the oscillator. The 1K resistor and 2N3904 are just guesses, as I don't know what the peak oscillator current will be. If you want to control the pulse period and the pulse frequency independently, you will need two 555, or a 556. One as an astable followed by one as a monostable.

Ken
 

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could you make me a diagram to show me where i connect the "+" and "-" out puts of the 555 timer to the transistor and to the main circuit?
 
The design should work, but the component values are just from another circuit and would need to be changed to meet your specific timing requirements.

Ken
 

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thank you very much,.. so the 1.5-3v and the 9v share the same gnd?
i have included pic for one part off the schematic i dont understand...
 

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Yes. The little triangle is just a symbol for a common or ground reference...you can ignore it.

Ken
 
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