Automatic temperature alarm: When the temperature rises to a certain value, the mercury thermometer mercury rose to the surface at the wire, mercury is a conductor. So the solenoid circuit is turned on, the electromagnet to attract spring, so that the bell circuit is closed, electricity rang the alarm, when the temperature dropped, leaving the magnet wire plant mercury surface, solenoid circuit is disconnected, spring back, and bell circuit breaker open, bells no longer sound.
Thermal Reed Relays (Thermalreedrelay) and solid-state relay (SSR: Solid-staterelay) works
Thermal reed relay is a use of thermal magnetic detection and control the temperature of the new thermal switch. It consists of temperature-sensitive magnetic, permanent magnetic reed switch, thermal installation piece, plastic substrate and some other accessories. Thermal reed relay coil not energized, magnetic steel and magnetic force generated by the permanent magnetic drive switching. Can Hang ring to provide a magnetic reed switch is determined by the temperature characteristics of the temperature-sensitive magnetic ring.
Solid state relay is a two terminal as an input, and the other two terminals for the output of the four-terminal device, the intermediate use of isolation devices are electrically isolated input and output.
Solid-state relays can be classified according to the type of load power supply AC type and DC type. Press the switch types can be divided into normally open and normally closed. Isolation can be divided according to type of hybrid, transformer isolated and optically-isolated, with optical isolation for up to