✍ A solid state relay (SSR) is just what it sounds like; an IC that acts like a mechanical relay. They allow you to control high-voltage AC loads from lower voltage DC control circuitry. They accomplish this by using infrared light as the ‘contact,’ a solid-state relay is really just an IR LED and a phototriac sealed up into a little box. Solid state relays, have several advantages over mechanical relays. One such advantage is that they can be switched by a much lower voltage and at a much lower current than most mechanical relays. Also, because there’s no moving contacts, solid state relays can be switched much faster and for much longer periods without wearing out. - - - - - - - - - - - - - - - - - - - - - - - - - - - ▼ Features: Anti-vibration, anti-shock No mechanical strain No mechanical moving parts No noisy action Fast response time Low control power Long life, 50-100 times longer than electromagnetic relays While triggered at low level means the voltage between the signal triggering terminal (CH1) and negative supply voltage is 0V, or the voltage at the triggering terminal is lower than positive supply voltage. If it lowers to a triggering voltage, the relay will pull in. It generally connects negative supply voltage and triggering terminal together. ▼ Specifications: Input voltage: 5VDC Maximum Output Current: 2A Maximum Output Voltage: 240VAC Operating Current: 12.5mA (per channel) Input Impedance: 440 Ω ±20% Trigger Voltage: 3.3 ~ 5V DC Reset Voltage Rating: 1V Input Voltage of Control Signal: [Low-trigger] 0 ~ 2.5V (low level state), the relay will be on; 3 ~ 5V (high level state), the relay will be off [High-trigger] 0 ~ 2.5V (low level state), the relay will be off; 3 ~ 5V (high level state), the relay will be on ▼ Package Content 1 x SSR relay module