mini dimmer with photoresistor

Mini dimmer

I have conceived this schematic with the purpose of prolonging the lifespan of the light bulbs used in the block of flats where I live.

Caution! This does NOT work for energy saving light bulbs; the electronic scheme of these bulbs generates self-induced voltage higher of 600V and the triac burns.

Because of the high voltage in the network (235-238V) and of the repeated switchings of the presence senzor the light bulbs of 60W/220V died in some places at aproximately 7-10 days. This device allows adjusting the voltage applied to the lamp in between zero and the network voltage with the help of a potentiometer. In this way the lifespan of the bulb is increased up to ten times depending on the applied voltage.

In order to obtain a decent light and brightness I have used two bulbs in parallel, of higher power (75W) that I have powered at 190V. Consequently I have obtained two bulbs of aproximately 50W that have been properly functioning for the past 6 months without burning.

The schematic and the wiring diagram have been projected in Sprint Layout.

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L1 and L2 pins are linked in series with the two light bulbs to the AC network (in my case through the relay contact of the presence sensor).

The functioning principle is explained below:

When the instantaneous value of the AC voltage exceeds the opening voltage of the DIAC (aproximately 30V) the triac will open and conduct up to the natural canceling of the current through the circuit. This happens symmetrically for both parts of the waveform. C1 capacitor is charged via R2-R1, decharges through DIAC1 and the gate of T1 triac and has the purpose of delaying the opening of triac reported to the moment when AC voltage passes through zero. In this way it will power longer and the average value of voltage at the pins will be lower.

The photocell is optional and it will lead to turning on the light bulbs only at night. Its value at dark must be of at least 2Mohms. This will have to be introduced in a plastic tube, black on the inside, and directed towards the source of natural light. Under no circumstances it should be exposed to the light bulb it is associated to. I have not used this component because the motion sensor already has one built in. Using a photodiode is not possible because it will act differently on the positive and negative part. In direct polarization it will basically shortcircuits the capacitor and the brightness will be zero while in reversed polarisation will work normally (the sensitivity was lower with the photodiodes that I have tried).

 

I'm a newbie to world wide electronic hobbyists and I try to publish my work and I don't know how can I do this without be considered a spammer. I have a lot of electronic projects (my own projects) and I want to publish them correctly. Can anyone advice to me?

 

Ok. I'll do like that.
Thank you.