Light control - Electronic Circuits Projects Diagrams Free

adumas · 22nd August 2007, 02:25 PM

Hi... I have constructed the following circuit which runs fine on 9V. The circuit responds to light and dims/brightens the LED.

Using this concept, I would like to put this circuit in line with a 120V outlet and power strip and essentially use it as a control valve.

Based on the light intensity, only so much current will flow from the wall socket through the circuit and to the power strip. If the light is totally lit, the full AC current runs through the circuit over to the power strip. As the light dims/increases, the AC current is also diminished/increased.

I need help in modifying the circuit to do this extra "control valve" process.

120V outlet
connected to following circuit

HTML Code:

			+ 9V
			  |
		_____________________
		|		    |
		|		    |
		|		    |
		<		    <
		> 150 	        470 >
		<		    <
		|		    |
		|		    |
		|		    __		
		|		    \/	LED
		|		    __
		|		    |
		|_________________|/   2N4401	   
		|		  |\			   
		|	            |
		|		    |
	        |		    |
		<		    |
		> PhotoCell	    |
		<		    |
		|		    |
		|		    |
		__________|__________
			  |		
			_____	
			 ___
			  _

ronsimpson · 22nd August 2007, 02:38 PM

http://www.epanorama.net/documents/l...ghtdimmer.html

adumas · 22nd August 2007, 07:09 PM

Hi... Thanks for the url - I checked it out and read over the material. Very interesting but it seems a bit overwhelming - so many choices / issues...

I'm wondering if the circuit I built can be modified - or if I just have to scrap it all together - which would be a shame.

ronsimpson · 22nd August 2007, 07:13 PM

What you built is for 10VDC. Transistors are for DC. A triac is a high voltage AC device.

adumas · 22nd August 2007, 07:48 PM

ok...

I went back to the url and found their simplist example. It is hard to read but here is the one they referenced. I'm assuming that instead of the 185K pot, I would substitute my photocell. Is that right?

HTML Code:

Black o--------------------------------+--------+
                                           |        |
                                        |  |        |
                                     R1 \  |        |
                                  185 K /<-+        |
                                        \  v CW     |
                                        |         __|__ TH1
                                        |         _\/\_ Q2008LT
                                        +---|>|   / |   
                                        |   |<|--'  |
                                    C1 _|_  Diac    |
                                 .1 uF --- (part of |
                 S1                     |    TH1)   |
    Black o------/ ---------------------+-----------+

Also, this circuit involves a TH1 Q2008LT triac. I searched the web site, All Electronics, and they have a:

Teccor Q4015L5. Alternistor Triac - Specifically designed for applications which are required to switch highly inductive loads. 15 Amps, 400 Volts. TO220 package.

Would this work?

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22nd August 2007, 02:25 PM	(permalink)
adumas	Light control Hi... I have constructed the following circuit which runs fine on 9V. The circuit responds to light and dims/brightens the LED. Using this concept, I would like to put this circuit in line with a 120V outlet and power strip and essentially use it as a control valve. Based on the light intensity, only so much current will flow from the wall socket through the circuit and to the power strip. If the light is totally lit, the full AC current runs through the circuit over to the power strip. As the light dims/increases, the AC current is also diminished/increased. I need help in modifying the circuit to do this extra "control valve" process. 120V outlet connected to following circuit HTML Code: + 9V \| _____________________ \| \| \| \| \| \| < < > 150 470 > < < \| \| \| \| \| __ \| \/ LED \| __ \| \| \|_________________\|/ 2N4401 \| \|\ \| \| \| \| \| \| < \| > PhotoCell \| < \| \| \| \| \| __________\|__________ \| _____ ___ _

22nd August 2007, 02:38 PM	(permalink)
ronsimpson	http://www.epanorama.net/documents/l...ghtdimmer.html

22nd August 2007, 07:09 PM	(permalink)
adumas	Hi... Thanks for the url - I checked it out and read over the material. Very interesting but it seems a bit overwhelming - so many choices / issues... I'm wondering if the circuit I built can be modified - or if I just have to scrap it all together - which would be a shame.

22nd August 2007, 07:13 PM	(permalink)
ronsimpson	What you built is for 10VDC. Transistors are for DC. A triac is a high voltage AC device.

22nd August 2007, 07:48 PM	(permalink)
adumas	ok... I went back to the url and found their simplist example. It is hard to read but here is the one they referenced. I'm assuming that instead of the 185K pot, I would substitute my photocell. Is that right? HTML Code: Black o--------------------------------+--------+ \| \| \| \| \| R1 \ \| \| 185 K /<-+ \| \ v CW \| \| __\|__ TH1 \| _\/\_ Q2008LT +---\|>\| / \| \| \|<\|--' \| C1 _\|_ Diac \| .1 uF --- (part of \| S1 \| TH1) \| Black o------/ ---------------------+-----------+ Also, this circuit involves a TH1 Q2008LT triac. I searched the web site, All Electronics, and they have a: Teccor Q4015L5. Alternistor Triac - Specifically designed for applications which are required to switch highly inductive loads. 15 Amps, 400 Volts. TO220 package. Would this work?