The proposed 4 step touch dimmer circuit can be used for dimming lights in 4 discrete steps using finger touch operations, and also fan seed can be switched up down in 4 steps with finger touch control
Electric light of any kind can be adjusted with this four position touch dimer to very low, low, medium and up to maximum limit – in most cases this will be with suffice.
With this an electric light is very well-controllable over a huge range of brightness. However, it is questionable hoe often this facility can be used. Position control has plenty of practical advantages in everyday use.
The 4 step touch dimmer switch circuit is built up on an LS7237 and some discrete components. Moreover, one can use the dimer as an electronic switch working for on and off. The advantage of such switches are, they do not produce sparks and do not make noise in nearby electronic devices.
One can also leave the pin 2 open, where the three position dimer ensure low, medium and maximum.
How the Circuit Works
The LS7237 comes with all the important facilities to control and drive a silicon-controlled rectifier (SCR) Tr1.
A 50 hertz signal is being filtered from the mains by R1, i.e. resistor and the capacitator, i.e. C4. This signal synchronizes the on-chip phase looked loop.
The supply for the LS7237 is being provided by the network of R1, C2, and D2. While unwanted noise from reaching the mains supply is being prevented by L1/C1.
As long as different sort of triacs can provide the required current, they are usable and are absolutely fit for operating voltage, However, such voltage should not be less then 400 V.
For the sake of safety, there must not be any deviation from the stated voltage rating, i.e. 400 V. The two 4M7 resistors ensure safety of the user – therefore under no condition they should be replaced by a single 10 MΩ resistor.
The complete circuit of this 4 step 220V fan light touch dimmer is small enough to fit for the pattress or plaster box of a switch that is used to turn on or off the light.