Presented by:-Jitendra Jangid

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Electrostatic Switch

Electro Magnetic switch

Cantilever switch

Switch using hall effect

Pizeo-resistivity switch

Cantilever switch using chemical process

Optical switch

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Electrostatic switch :1. large gap of at least 100 micro meter between the electrostatic

plates is required

to prevent arcing during a possible high voltage surge on the order of 2000 volts

2. Maximum device size of 1mm x 1mm

3. Device withstand 3 Amps current for one second for the contact part of the relay.

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When Fe is larger than Fm, the electrodes move closer; the distance between the electrodes is reduced.

However when the distance between the 2 electrodes is lesser than 2/3 of the original gap, the electrode collapses.

This phenomenon is known as pull-in.

This phenomenon is commonly used in

g-switch design

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It takes large time for switching it required additional reference voltage tomoving effectively

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When voltage is applied to the electrodes, the electrostaticforce acting on the electrodes pulls down the cantileverbeam toward the ground.

When the beam is pulled away from its equilibrium position, stresses accumulate in the beam . The stresses form a resultant force to counterbalance the electrostatic force.

When the applied voltage is removed, the counter-balancing force returns the beam back to its normal position. This force, which is the sum of the stresses in the beam, is referred to as the restoring force that "restores" the beam to its original position.

The shorting bar is a thin layer of gold foil located below the cantilever beam and moving along with the beam.

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Advantage:

Good Sensitivity

Excellent temperature stability

Integrated electronics enable 0.01A or smaller resolution

Limitation:

Small signal

Undesired electrostatic actuation

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The piezoresistive effect describes the changing electrical resistance of a material due to applied mechanical stress.

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Advantage :-

Large sensitivity of simple resistors

Very easy to fabricate and low cost.

Limitation:

Too sensitive to temperature changes

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The Hall effect refers to the potential difference (Hall voltage) on the opposite sides of an Electrical conductor through which an electric current is flowing, created by a magnetic field applied perpendicular to the current

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Advantage:

Immune to dust, dirt and water when appropriately packaged.

Limitation:

Very low signal level, an amplifier is required.

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Space division switches

– 2D MEMS

– 3D MEMS optical switches

• Spectral domain processors

– Wavelength-selective switches

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◦ Low Size

◦ High switching speed

◦ High sensitivity

◦ Low noise

◦ Reduced cost

◦ Batch Processing

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Thank you

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