Transcript:
[0m:00s] Hey, it’s Mitchell and welcome to another video in the RSP education series. What if I told you there’s a relay that never wears out, switches in microseconds, and makes zero noise? Meet the solid state relay or SSR. It’s a very silent powerhouse that revolutionizes automation. No sparks, no delays, just pure electronic precision. Let’s break down how solid state relays work and why they’re taking over industries. If you like this content and want more educational videos, like and subscribe. This video also 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.
[0m:47s] So solid state relays, SSRs, the way they work, there’s no moving parts. A traditional relay like an electromechanical relay uses mechanical contacts that physically open and close that can wear out over time like we discussed. Solid state relays use semiconductor components like thyristors, triacs, or MOSFETs to switch power electronically. No physical movement means longer lifespan and no contact arcing. The technology is actually really cool. Starting with optocoupler isolation, solid state relays have an LED light as a light source and a photo detector as a light sensor. When the control signal turns on the LED, the light activates the photo detector which then triggers the output switching.
[1m:39s] Why this matters is it keeps the control circuit, a PLC for example, electrically isolated from the high power load. This prevents noise or voltage spikes from damaging sensitive electronics like PLCs. Another pro of SSRs is instant switching. Electromagnetic relays have a slight delay because the mechanical armature needs time to move. SSRs switch instantly because it’s all electronic. This is great for fast repetitive tasks in automation.
[2m:18s] A real world example in automation is a PLC controlling a heater in a factory. With an electromagnetic relay, every time the PLC turns the heater on or off there’s a tiny delay and mechanical wear. With an SSR, the switching is silent, near instant, and lasts much longer because there’s no physical contact or moving parts that degrade. Solid state relays are like the digital version of relays. Faster, more reliable, and longer lasting, but usually more expensive than traditional electromagnetic relays. They’re ideal for high speed or frequent switching in industrial systems.
[2m:56s] Some pros are no mechanical wear, much longer lifespan with millions of cycles, silent operation, and fast switching with microsecond response times. Some cons are heat generation requiring heat sinks for high current applications, leakage current, and voltage spike sensitivity requiring protection circuits. Common applications include PLC output modules, temperature controllers, and high frequency switching like CNC machines. To recap, no moving parts equals no wear and tear, optocoupler isolation protects your PLC, and instant switching is perfect for high speed automation. For a full line of relays and hundreds of thousands of other industrial automation products, visit our website at rspsupply.com.