We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What is a Diode Limiter?

By Paul Scott
Updated: May 17, 2024

A diode limiter is an electronic circuit designed to clip or limit an alternating current (AC) supply voltage or an audio signal to a preset value. This is typically necessary where the supply voltage is larger than needed or powerful audio signals require compression to prevent overloads. Diode limiter circuits achieve this clipping function by placing one or two Zener diodes in parallel with the supply or signal. A single diode will only clip one half of the wave form while a pair of diodes will clip both negative and positive parts of the cycle. Accurate limiting is possible due to the known voltage limiting characteristics of different Zener diodes.

Any AC power supply or audio signal is made up of a sinusoidal or sine wave form. A sine wave is a smooth repetitive series of positive and negative peaks with a zero value in the center of the wave form. The height between these peaks and the zero point define the amplitude or size of the signal or supply. A diode limiter can control the amplitude of a signal if it is too large by either clipping one half of the wave or both. Producing a precise reduction in amplitude with a diode limiter is possible due to the unique, accurate voltage limiting abilities of Zener diodes.

This accurate cut-off characteristic allows a Zener diode to limit the voltage it passes at a predetermined level. If a single diode is inserted across the power supply or signal output, it will limit one half of the wave form to its rated voltage. If a second diode is inserted in the circuit in the opposite direction or bias orientation to the first, then both the negative and positive halves of the wave form will be limited. These diodes are typically accompanied by one or more resistors in the voltage limiting circuit which aid in producing a well controlled output voltage.

The diode limiter has many uses in both electronic and audio applications where it is used to produce low working voltages from a single higher supply voltage or to compress excessively powerful audio signals. Diode limiters are simple, efficient, and accurate voltage controllers which take up minimal physical space on circuit boards. These circuits are also a particularly cost effective way of controlling voltage outputs. There are also a myriad of available Zener diode ratings which gives circuit designers flexibility in the exact voltage produced by the diode limiters use in their circuits.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
By everetra — On Jul 11, 2011

@SkyWhisperer - That’s definitely not something you want to try at home. I recommend you just stick with a current limiting diode to get the results you want.

They’re fairly inexpensive and they can regulate voltage over a wide range of current and voltage levels. They give you more control over what you’re trying to do.

In other words, they're not just glorified fuses, which is what your light bulb solution is. I’m with you, however. Do-it-yourself stuff should be avoided when it comes to electricity.

By SkyWhisperer — On Jul 10, 2011

While I don’t recommend that anyone try this, I’ve heard of people rolling out their own do-it-yourself current limiter devices.

For example, one guy uses a light bulb to accomplish this. Electricity from the electrical outlet passes through the light bulb and then continues on to the target device. Any current overflow will blow out the bulb first.

Since it’s a series circuit, the current overflow pretty much ends the flow of electricity, and your target device is saved from being fried.

Like I said, I don’t recommend that you try that. The diode resister mentioned in the article seems like the more orthodox approach. But people do have their own creative solutions to deal with voltage overflow problems; I just prefer to leave creativity alone when it comes to electricity.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.