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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
 

NickLee

New Member
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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KMoffett

Well-Known Member
Google: "photomos relay"

Ken
 

KMoffett

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

Ken
 

KMoffett

Well-Known Member
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
 

NickLee

New Member
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
 

KMoffett

Well-Known Member
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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NickLee

New Member
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?
 

KMoffett

Well-Known Member
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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NickLee

New Member
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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KMoffett

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

Ken
 
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