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A History of Microswitches


The humble microswitch will be 90 years old this year, with the first design of its kind first invented in 1932. Since then the devices have undergone various innovations but have always maintained their original premise, which is to be an electric switch actuated with only a very small amount of physical force.

Microswitches and the likes of Senotec switching amplifiers are used in a wide variety of industries for different applications. The primary use of a microswitch is when a low driving force with a clearly defined action is required. A secondary use is for long-term reliability, as the construction and operation of microswitches makes them very durable over a long period of time. This is because the internal mechanism of the closing force on the contacts of the switch are independent of the operating force.

How Microswitches Work

Microswitches can vary in design, but one common model features two conductive springs on the inside, with a long and flat spring hinged at one end of the switch and the electrical contacts connected at the other end. A smaller and curved preloaded spring then tries to extend itself, connecting with the long and flat spring both at the point near the contacts and at a fulcrum near the midpoint of the flat spring. This causes an actuator nub to push against the flat spring near its hinge point, but because the flat spring is anchored, the curved spring cannot move it and instead pulls the flat spring upward and away from the anchor point.

The actuator nub then flexes the flat spring while the curved spring maintains a connection between the now touching electrical contacts. At the peak of the flex, the flat spring begins to compress the curved spring which moves the contacts.

Microswitch Applications

One common application of microswitch products that the layman will know is the door locking mechanism of a microwave oven. They are also used as safety switches in lifts, as well as in vending machines and the buttons of arcade games. Microswitches are also used to detect paper jams in photocopiers.

Senotec switching amplifiers are often used as tamper switches on gate valves in water pipe systems and applications using other fluids. This is because it will be necessary to know when to switch off the valve when a container is full.

Many other home appliances use some form of microswitch, plus they and Senotec amplifiers are frequently found in all sorts of industrial machinery and controls, vehicles, and pretty much anywhere there is a need for precise control of electrical circuits.

If you require any Senotec switching amplifiers, then contact YB Components who are the UK’s leading Senotec suppliers. Local stocks are kept of Senotec switching amplifier products so they can be shipped fast and free all over the UK and the rest of the world.