Many Electronic circuit projects in simple ways of learning

Many AC Dimmer circuit ideas

If you are looking for the AC light dimmer circuit. Here is simple and TRIAC dimmer circuit.  They can control a light bulb, speed AC motor. They use the TRIAC and SCR as the main component and adjust potentiometer and switches.

Many AC dimmer circuit ideas

See more projects circuits below:

  • Low volts AC Dimmer for 6.3V Lamp
  • Very Cheap AC light dimmer circuit
  • Automatic Light Dimmer Circuit
  • AC 100W Lights TRIAC Dimmer circuit
  • AC light dimmer circuit using TRIAC and DIAC
  • How to build AC light Dimmer
  • Modify AC Dimmer to the automatic lighting


Low volts AC Dimmer for 6.3V Lamp

Low volts AC Dimmer for 6.3V Lamp

This is a low voltage AC dimmer circuit, for lamp 6V. While friends may not see the benefits of this circuit. But I think that its advantage in the first step, we will learn the working of  TRIAC. Second, high safety, because of Low AC Voltage.

Which they have the working is simple.  The UJT-Q1, D1, VR1, C1, R1, R2 will generate frequency to actives the TRIAC. Then it makes the Lamp bright up.

Which the working rate of the TRIAC can be controlled by potentiometer-VR1.

So It is simple dimmer.

We may apply other level voltage of power supply, like  AC12V.

The Q1 is UJT – 2N4891 or others.

I hope this circuit will be ideas for friends.

Very Cheap AC light dimmer circuit

Very Cheap AC Light Dimmer

Next, this is a very simplest AC light dimmer circuit, easy and inexpensive.

In the above circuit, we use the dimmer circuit with the AC power line.

So we must be very careful.

How it works
Turn on S1 to ON and Select S2 to dimmer mode.

We use a capacitor in series with a lamp. The capacitor reduces power to the lamp.

S2 chooses an output power, full or less.

The value of capacitor-C1 depends on the size and power of the lamp, required brightness.

We may use several capacitors, to select the different capacity.

C1 should be a polyester capacitor or metalized polypropylene capacitors.  And higher voltage than 400V.

Do not use the electrolyte capacitor in this circuit.

If the output short circuit, the C1 capacitor is damaged immediately.

Automatic Light Dimmer Circuit

This is an automatic light dimmer circuit. You do not need to dim the lights by yourself. It is so very convenient because we use the LDR to detect external light. To control the Triac and the brightness of the lamp next.

Automatic Light Dimmer Circuit

– Suppose low light so there is the voltage across the LDR many making the TRIAC a lot of work, the lamp so super bright. But sometimes the light is very high so a few voltages at Triac, then the lamp do not work or low bright.

-This circuit we used only an incandescent light bulbs size AC220V 50Hz at 5 watt because low power triac and basic circuit. You should not be touch the circuit. you may be to get electrocuted.

AC 100W Lights TRIAC Dimmer circuit

AC 100W Lights Dimmer Using A TRIAC

This is a simple AC TRIAC dimmer circuit. This circuit can dim the lamp up to 100W. If the TRIAC is a high temperature. It should be held with a large heat sink.

The DIAC(Diode AC bi-directional switch) is kind of diode. It switches AC voltage or trigger to a gate of the TRIAC.
Adjust  VR1 to dims the brightness of the lamp.
Caution!  this circuit must be in an electricity insulation box that closes all the time. It has high voltage electricity flows through.

AC light dimmer circuit using TRIAC and DIAC

AC lights dimmer circuit using Triac and Diac

 AC light dimmer circuit using TRIAC and DIAC (update from the Previous circuit)

Operation of the circuit
The lightness of lamp-L1 is adjusted by  VR1.  The VR1 controls speed of charging of C1. Because triac will work.

When C1 has charged to the voltage at the TRIAC work. When adjusting the VR1 C1 will charge as little faster lamp is lit. If the adjustment of VR1 C1 will charge very slowly.The little light bulb.

Because the TRIAC  does not work over the TRIAC during the work. The light bulb will dim down by adjusting VR1. The R1 is placed for protection VR1 prevent damage.

R2 and C2 eliminate the disturbance signal, both inside and outside the circuit.

How to build  TRIAC AC light Dimmer

This is Power AC Dimmer 1200W. It uses the TRIAC Q4006LT. Friends ever tour is the foreign land has and to ever reach rest a hotel. On bed head has will head bed fire decorates. It has a button opens-close and a button controls the brightness of the equipment this/these be AC Dimmer follow our circuit can adjust to decorate.

1200 Watt AC Dimmer by Triac Q4006LT

The VR1 for control the light beside when friends apply for TRUE work. The Q1 – Q4006LT, should hold heat sink with and should be careful specially prohibit catch one ( part ) which part in the circuit because read will bump against the electricity can suck. I hope this circuit, friends can induce apply be AC Dimmer with electric other appliances bump against emphasize kind coil heat equipment, be lucky please yes.

Figure 2 the pcb layout and Components layout of this circuit.

Note: Fuse you should as the current load. for example we use 100Watt lamp we will use fuse current is 100 watt / 220V = 0.45A or 0.5A.

Good suggestion

Mr Gerson said about: 1200 Watt AC Dimmer by Triac Q4006LT
Why is 1200W dimmer when it uses 0.5A fuse? Is it should 5A fuse?

When you 0.5A fuse. It should be 120W dimmer by the maths.

Let’s calculate again:

Power (apparent since AC) = VI(rms) = 220Vac x 0.5A = 110VA (maximum, because of limiting of fuse)

Let’s assume a power factor of 1 (not possible in real using, unless 3 phase)

Power_in (max) = 110W.
Power_in (let’s said pf=0.7, realistic case) = 110 x 0.7 = 77W, this is more realistic power input.

So if power input is only about 77W. Please tell me. How it could output 1200W?  It’s impossible according to the law of conservation of energy. The fuse will just BLOW every time it switches on at full brightness.

To get 1200W input for the typical realistic case.

You need:
Fuse rating (Irms)
= Pr / (V * pf)
= 1200 / (220 * 0.7)
= 6.5A

Sure! You may not need the many currents. Since it is a dimmer. But at maximum brightness. You need to use 6.5A current. Otherwise, I am sure something will blow (the fuse).

Modify AC Dimmer to the automatic lighting

Way to modify an AC dimmer into a light switch circuit, to turn ON-OFF and automatic light dimmer or two in one form. Since the general dimmer uses TRIAC to control a load like a relay contact. So we can easily make it by a few parts.

The automatic night light dimmer circuit
automatic night light dimmer circuit
See Figure 1.
We put the parts includes S2, LDR, and RA-33K, 1/2W or RB to the AC dimmer circuit.

Turn-on a switch-S2, this circuit becomes the automatic light switch circuit.

When no light (or night) to LDR, the circuit will be closed, the lamp as the load will glow.

And a potentiometer VR-500K adjusts the sensitivity.

This can control a outdoor or car park lamps to ON with itself and OFF in day. LDR1 a kind NTC is when the light hits it, then its resistance will decrease.

The automatic Day light dimmer circuit
automatic Day light dimmer circuit

But in Figure 2 will work to reverse the first. Also, choose the switch-S2 to LDR1 way, then this circuit becomes the automatic daylight dimmer switch circuit.

This can control lamps in the Warehouse, if open the door and have sunlight to LDR, will cause the lamp to glow.

LDR1 in Figure 2 is a PTC type. When the light strikes it. It will increase Resistance instead. This makes it possible to control the on-off. Or appropriate to the dimmer light outside.

LDR may be installed on the box or outside. But the important need far from the light enough. It will be a circuit does not operate correctly.

We can solder the more devices to the PCB and S1 may install in a box for safety when used.

‘3000 watts Dimmer for Inductor Load ’ »

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This Post Has 12 Comments

  1. Thanks for this simple circuit

  2. what is the name of software this schematic is created by?

  3. how can i design atriac circuit to control speed of motor 0.5kw?

  4. can i havve the ckt for time period of 10 sec

  5. hello
    i dont full speaking english I want a circuit automatic ligh by senosr pir for turn off & turn off lamp (220AC) that day tur off & in night turn on whitout transformer for power sourc ic&…& whitout microcontoroler

  6. what is the LDR used here? there is lot of confusion Here the LDR should act like a conductor at night and resistor in morning. so that the circuit works accordingly.

  7. I’ll try to use R2, C2 to eliminate the noise. thx.

  8. Can you be mo specific on what kind of diac to use in you figure 2 by L circuit?


  10. Pingback: Quora

  11. sir, i have 0.36uf/400v capacitor, what are the changes needed to the circuit

  12. The English in this article is very poor, at times its hard for a student such as myself to understand. I ask the author to please make an effort to fix this otherwise fantastic article.

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