IR receiver oscillates if powered by rectified source. help?

folarinv

New Member
I constructed an infra-red receiver using IR-sensor from TV, schmitt trigger-4093, monostable-555, flip-flop:4013, transistor and relay. I'm using this receiver to switch on/off a lamp. The problem with the circuit is that if i power it with a rectified voltage source, the lamp will start going on/off by itself (oscillation) but if i power it from a 9V battery source, the circuit behaves properly.

How can I modify the circuit so that I can power it with a rectified voltage source as the 9V battery gets drained within minutes.
 
Re: IR receiver oscillates if powered by rectified source. h


If you mean a three pin IR receiver IC?, these need seperate supply decoupling, feed the IC power through a resistor with a decoupling capacitor - check my IR PIC tutorials for details of suitable values.
 
regulated power supply did not work

I used a 9V regulated power supply taken from an hobbyist kit but it did not stop the oscillation.

Nigel, I'm not clear with your suggestions when u said i should decouple the power supply to the 3-pin IR receiver. Secondly, your PIC tutorial site talks about programming. I couldn't find much help there.
 
Re: IR receiver oscillates if powered by rectified source. h


Nigel, I'm not clear with your suggestions when u said i should decouple the power supply to the 3-pin IR receiver. Secondly, your PIC tutorial site talks about programming. I couldn't find much help there
 
Re: IR receiver oscillates if powered by rectified source. h

 
I used a 9V regulated power supply taken from an hobbyist kit but it did not stop the oscillation.
If you have an oscilloscope, look at the 9 volts. It is probably rippling w/ a 60hz sine wave. Or try powering a radio or something that usually requires a 9 volt battery with it and you will probably be able to hear a hum.

My point being is that your power supply is probably nowhere near being clean.
 
Re: IR receiver oscillates if powered by rectified source. h

 
Re: IR receiver oscillates if powered by rectified source. h

folarinv said:
The circuit seems to be stable now. I've been testing it for over 48hrs and
it has not make any unsolicited switching.I used a 470resistor and 47uf capacitor for a 9V power supply. I just hope it remain stable forever.

It should do, you shouldn't have left them out in the first place, as I said before they are absolutely vital for these IR receiver IC's.
 
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