Transcript:
[0m:00s] Hey, I’m Mitchell and welcome to another video in the RSP education series. What if you could switch massive industrial power loads at lightning speed without a single moving part, spark, or sound? Enter the solid state relay. We’ve talked about it a bit in the past, but today we’re going to dive in deeper. It’s the silent ultra fast powerhouse of industrial automation. In this deep dive, we’re going to crack open how solid state relays use light to safely isolate control signals from high voltage circuits with no physical connection, no noise, and no wear and tear. We’ll also compare them head to head with traditional electromechanical relays across speed, lifespan, noise, and more. If you like this kind of content and want more educational videos, like and subscribe. This video is for educational purposes only. Consult a professional for your application. RSP Supply is not liable for any misuse of this information. Let’s dive in.
[1m:02s] Solid state relays use electronic parts with no mechanical switches to turn circuits on or off, allowing for safety and isolation. On the input side, a tiny LED light turns on when a control signal is sent. On the output side, a light sensor or photo detector sees the LED and triggers a power switch like a triac or MOSFET to handle the high voltage load. Because there is no physical connection, the control circuit and the high power load never touch. This prevents shocks, damage, and noise issues. Unlike mechanical relays, SSRs do not spark or bounce and are not affected by electrical interference. The bottom line is that SSRs use light to safely link a control signal to a high power circuit with no moving parts.
[1m:49s] Let’s compare solid state relays with traditional electromechanical relays across five key features. First is speed. SSRs switch incredibly fast in microseconds to milliseconds, while EMRs are much slower, typically five to fifteen milliseconds per operation. For lifespan, SSRs last for millions of cycles with no moving parts to wear out, while EMRs typically survive fifty thousand to five hundred thousand cycles before contacts degrade. Noise is another major difference, as SSRs operate completely silently while EMRs have the classic relay click.
[2m:25s] Shock and vibration resistance is another factor. SSRs are immune to physical impact, while EMRs can suffer from contact bounce when shaken. Sparking is also a key difference. SSRs are completely spark free, while EMRs create visible sparks every time they switch under load. So when should you use each? SSRs win for speed, longevity, and silent operation, but EMRs still have their place for high power applications.
[2m:50s] When working with SSRs, remember that they generate heat because of internal resistance called on state voltage drop. Even a small one volt drop at ten amps means ten watts of heat, and heat increases rapidly as current increases. Unlike electromechanical relays that waste almost no power when closed, SSRs always have inherent power loss. To recap, solid state relays offer microsecond switching, silent operation, and long lifespan, while electromechanical relays handle brute force high power tasks but switch slower and wear over time. If you need fast, silent, maintenance free switching, SSRs are the better choice. For a full line of relays and hundreds of thousands of industrial automation products, visit rspsupply.com.