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Idea for an electronic AC switch circuit

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jamed

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hi:

when we need to turn on or turn off a device"load" by using computer ,
we use transistor if the device work on DC and(electronic switch)
we use relay if the device work on AC(electromechanical switch) .

i have this circuit to make full electronic switch for AC device:-
52_1331134186.jpg


i test this circuit in simulation program(circuit maker) ,it work fine.

what your opinion?
 
Last edited by a moderator:

Re: Electronic AC switch

why -v & +v ? (both)
 

Re: Electronic AC switch

jamed said:
hi:

when we need to turn on or turn off a device"load" by using computer ,
we use transistor if the device work on DC and(electronic switch)
we use relay if the device work on AC(electromechanical switch) .

i have this circuit to make full electronic switch for AC device:-
52_1331134186.jpg


i test this circuit in simulation program(circuit maker) ,it work fine.

what your opinion?
Click to expand...

I think, the image circuit will not work, because in real applications, ac loads require ac components also such as SCR, DIAC, TRIAC, etc.

if you follow the image circuit will be very large short-circuit and will result in severely damaged transistor
 

Re: Electronic AC switch

Dont play with this dangerous circuit, outside from simulator.

Relay can be used on AC and DC. For higher current switching loads use contactors, or triacs (solid state relays), you can use MOSFETs, IGBT,...
 

Re: Electronic AC switch

but if he use relay there is no problem .(only said relay is not used in circuits)
 

Re: Electronic AC switch

thannara123 said:
why -v & +v ? (both)
Click to expand...
+v to run NPN transistor
-v to run PNP transistor
if you follow the image circuit will be very large short-circuit and will result in severely damaged transistor
Click to expand...
how short circuit can occur in this circuit?
 

Re: Electronic AC switch

Jamad safety glasses necessarily and safety on first place if You planning to test this.



Best learning is from experminets, but safety on first place.

I dont recommend to try this with HV 220V AC.


Also pay attention on transistors voltages and other data from manufacturer datasheets, the same is for diode ratings and data.
 
Last edited:

Re: Electronic AC switch

tpetar said:
Jamad safety glasses necessarily and safety on first place if You planning to test this.
Best learning is from experminets, but safety on first place.

I dont recommend to try this with HV 220V AC.


Also pay attention on transistors voltages and other data from manufacturer datasheets, the same is for diode ratings and data.
Click to expand...
If i will make experiment i will not make on 220 volt,
i will use 12 V AC from a power supply.
and off course i will use correct transistor and diode from data sheet.
 

Re: Electronic AC switch

jamed said:
hi:

when we need to turn on or turn off a device"load" by using computer ,
we use transistor if the device work on DC and(electronic switch)
we use relay if the device work on AC(electromechanical switch) .

i have this circuit to make full electronic switch for AC device:-
52_1331134186.jpg


i test this circuit in simulation program(circuit maker) ,it work fine.

what your opinion?
Click to expand...

Depending on the current the LOAD uses, we select the drivers. if small DC currents are used we use transistors but if large current is required we use either a relay or a SCR. If it is AC current we can use relay or Triac. So SCR's and Triacs are best solutions for Gating with computers to turn ON and OFF. when you are using AC in your circuit at crossover there is a brief discontinuity and if the load is inductive it generates enough back EMF to punture your transistors.
 

Re: Electronic AC switch

Hello jamed
U are on a very dangerous path !!! some things are just not done 220v or 12 or 1 volt
U need also respond to other posts offering to use relay and tell us why yes.or not.
If u need fast switching (like light dimmer )on /off thru computer say so .
Google for opto triac thats a really good solution .. unless u are rich and have a lot of money to buy a new computer (after u blow up the one u using and most positive all the other components like joy stick phone printer keyboard modem router etc..etc..) and *** FORBID PAY FOR A HOSPITAL BILL IF U GET ELECTROCUTED... or *** forbid u may even DIE.
 

Re: Electronic AC switch

Jamed,

You should know from other post familiar with this problematic, that transistor and triacs will dissipate some power into heat. ;-) Put transistors on appropriate heatsink.


And Jamed,
Let the force be with You,....
 

Re: Electronic AC switch

thank you guys
 

Re: Electronic AC switch

Hi Jamed

Your circuit makes sense, just make sure you use High voltage transistors like BU407 etc.

You can make the transistor bases common after the individual resistors and apply an adjustable PWM pulse there.

Initially use a low current AC load like a 25 watt incandescent bulb.

The PWM pulse at the bases should be applied preferably via an opto coupler
 

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