Make simple AC dimmer using NE555

We know that the PWM signal is very easy to generate and we can control DC loads using this PWM signal. If we could use the PWM pulse to drive AC loads, the control circuit would become very easy. This is why many people look for PWM-based driver circuits for AC loads. Here in this article, we will see how we can make a simple AC dimmer using NE555.

⚠️ Disclaimer ⚠️

Working with electricity involves serious risk. Ensure you have the necessary skills and take proper safety precautions before attempting any electrical projects. Proceed at your own risk — the author assumes no responsibility for any damage, injury, or issues resulting from the use or misuse of the information provided.

All content on this website is original and protected by copyright. Please do not copy or reproduce content without permission. While most of the resources shared here are open-source and freely accessible for your learning and benefit, your respect for our intellectual effort is appreciated.

If you find our tutorials helpful, consider supporting us by purchasing related materials or sharing our work — it helps keep the content flowing.

Need help or have questions? Leave a comment below — the author is always happy to assist!

Before we start the hardware please read this article first to understand how the PWM signal can be used to control AC loads.

Generating PWM signal using NE555:

There are different ways to generate a PWM signal for our MOSFET. We can use Analog or digital methods. We can use Op-Amps or Timer ICs or micro-controllers for this purpose. The easiest way for us who knows how to use micro-controllers is to use micro-controllers and the cheapest way is to use Timer ICs like NE555. But it depends on the field of use which circuit is the best.

PWM signal generation using NE555 Timer IC:

We can use NE555 timer IC to generate PWM with this circuit diagram:

Simulation Result:

AC load drive with NE555:

So if we combine this PWM generating circuit with our previous AC load driving circuit then we can control our AC loads using PWM generated by NE555.

Circuit diagram:

In this circuit diagram, the generated PWM signal is not sufficient to turn on the MOSFET. So we used an Opto-coupler to level up the gate voltage. A 12V DC source is required for that.

Signal pattern:

Here is the signal pattern of our simple AC dimmer using NE555:

The yellow signal is the Gate signal of MOSFET, the Blue one is at the Drain of MOSFET, and the red one is across the load.

Now we can easily control our AC loads using the PWM signal. Here we have generated PWM using NE555 timer IC which is very common.

Result:

After simulating and field testing, we have seen that we can control AC loads using a PWM signal. Although it generates little EMI, it made our work easy in many circuits. Considering load type and use we can implement this technique in our control circuit.

Check this out: 5 coolest multimeters you can buy