Relays are ill-suited for PWM applications and typically fails for everyday electronic systems. These devices function as mechanical contactors designed to toggle load states by physically moving contacts, and are fundamentally incompatible with high-frequency toggling. Their mechanical construction imposes critical performance barriers that prevent their effective use for PWM. Most commercial relays can switch at most a few times per second, while PWM often demands switching frequencies of dozens to hundreds or even thousands times per second to precisely control power to inductive loads such as LED arrays and DC motors.

If you attempt PWM via relay switching will immediately reveal several critical issues. To begin with, relay terminals wear out rapidly under high-cycle operation, causing premature failure. Moreover, response time is far too slow to produce a smooth average power output. What you get instead is a series of loud clicks and abrupt power changes that often trigger vibration, noise, or flickering in connected devices. Third, back EMF surge generated when motors or solenoids the relay opens can pitting the terminals and compromise any driving circuitry.

When precise power regulation is required, you should utilize semiconductor switching devices such as semiconductor-based relays. Modern semiconductor switches can toggle with microsecond precision over billions of cycles and with minimal power loss. are compatible with programmable logic circuits to provide precise control over the RMS value supplied to a connected appliance. A MOSFET equipped with a dedicated MOSFET driver IC and a heat sink can handle high currents and ensure consistent modulation reliably.

In cases where your setup that demands pulse width modulation and you are limited to electromechanical switches, you should reconsider your design. Limit the relay to basic state toggling, and implement PWM using a semiconductor switch. As an illustration: you might use a relay to turn a large heater on for a full cycle and a solid-state switch to modulate LED intensity during the same time window.

To conclude, using relays for PWM is unfeasible for high-frequency power regulation. The reliance on moving parts makes them too slow, acoustically objectionable, رله and prone to failure for the rapid toggling demands that modern control systems need. Always choose semiconductor switches like power FETs and bipolar transistors when you need PWM. Semiconductor switches respond quicker, produce no audible noise, more efficient, and far more durable for this type of application.