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R/F remote control switch for light

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alex76

New Member
Hi, I'm new to this forum. Have electronics background, but long time have not been practicing. So, I have lost knowledge of calculation of simple BJT or even looking at data sheets.

Right now, I'm making a R/F remote control switch for 240v wall light.
Thinking of saving the hassle to build the R/F sectioin, which most of the time not working in my case, I have bought an inexpensive remote control doorbell and make a modification from there.

I need a circuit that can do the latching at the rising edge of a clock and stays "High" at the fall edge. then the relay will go "low" at the next rising edge of the clock.
All I can think of is to use a 4017 decade counter and have it count 0,1 and reset back to 0, which means only 2 output. The relay will be tie to one of these output. The CLK of the 4017 will be fed from the output of the R/F Remote control.
The problem I'm facing right now, is the output of 4017 does not have sufficient current to drive the relay of 5V (120ohm, which is ard 40mA).
Base on the 4017 data sheet here https://www.fairchildsemi.com/ds/CD/CD4017BC.pdf
can anyone tell me what is the max output current of the decoded output if the VDD to the chip is 5V?
how can I modify to drive the relay?

Maybe someone have a better idea to do a latching circuit other than this of mine.

Thanks in advance for any help and suggestions.
 

Russlk

New Member
I would use a 4013 dual D flip flop, but the 4017 will work also. To drive the relay, use a TO-92 mosfet. The CMOS logic can drive the gate directly. Source to ground, drain to relay.
 

alex76

New Member
Russlk said:
I would use a 4013 dual D flip flop, but the 4017 will work also. To drive the relay, use a TO-92 mosfet. The CMOS logic can drive the gate directly. Source to ground, drain to relay.

thanks russ, would you be able to let me know any mosfet part number that I can get?
thanks
 

alex76

New Member
I wonder if I use 5V power supply for the decade counter, is the output sufficient to drive a NPN 2N3053 or 3904?
This is becasue I saw most circuitry are using either 9V or 12V supply.


Any suggestion?

thanks
 

Rescue1

Member
I am not trying to distract you from building your circuit,I can certainly appreciate a good project,but you can acheive your goal with some x10 components.Elk technologies makes a 200-240v box that can switch heavy loads by using the x10 signal.If you are not familiar with the x10 stuff,do a search on ebay,or go to radio shack.Whats good about going this route is you can control whatever it is from you computer,remote,keychain remote,desktop switch,vehicle...e.t.c..The possibilities are endless.Then you can control other devices around your home as well.I hope I could be of assistance...Good luck... :p
 
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