MME 3374a - Electrical Foundations for Mechanical Engineers - Unit 4

These flashcards cover key concepts related to power electronic devices, specifically focusing on switches and relays as discussed in the lecture notes.

Electromechanical switches and relays are primarily __ in nature.

mechanical

The contact type of a switch determines how __ is directed.

electrical current

Before closing, a switch contact can be either '__' or 'closed'.

open

Low-current switches can utilize technologies such as __, capacitive, and inductive.

mechanical

'Normally Open' (NO) contacts mean that current does not flow until the switch is __.

actuated

Operational temperature is an important factor in __ selection considerations.

switch

A switch's __ is required to break through contact oxidation that may form.

wetting current

In the context of switches, the phenomenon where contacts 'bounce' is known as __.

switch bounce

Hall-Effect sensors were discovered by ____ in 1879.

Edwin Hall

The Hall coefficient relates the induced electric field to current density and _.

applied magnetic field

A __ encoder provides a unique pattern representing each position of the shaft.

absolute

An incremental encoder consists of a series of __ waves.

square

The resolution of an incremental encoder is determined by the number of __ on the encoder disk.

slits

The two main types of incremental encoders are tachometer and __ encoders.

quadrature

Quadrature encoders use angular separation of degrees between channels A and B for direction detection.

90

A tachometer encoder can only detect __ but not direction.

speed

Optical switches consist of an LED transmitter and a __ receiver.

photo transistor

Solid state relays require __ to dissipate heat due to lack of moving parts.

heatsinks

The primary use of electromagnetic relays is to switch __ contacts.

high current

A __ switch is actuated using a solenoid, an electrically operated switch.

electromagnetic

An H-Bridge driver is typically used for __ motor control applications.

bidirectional

Electromagnetic relays isolate the control circuit from the __ circuit.

load

Switch contact degradation occurs due to __ upon opening.

arcing

The term IP ratings stands for __ Protection ratings.

Ingress

Optical switches can be used in applications such as __ feedback.

position

Hall-effect sensor applications include determining __ speed of a motor.

rotational

Normally Closed (NC) contacts allow current to flow until the switch is __.

actuated

For high-frequency operations, solid state relays are preferred over __ relays.

electromechanical

An electrical principle states that contact bounce can cause issues with __ control.

device

Relay contacts may engage or disengage depending on the drive of the __.

solenoid

The resolution of a 12-bit binary absolute encoder is calculated as 360° / __.

2^12

Optical switches operate by measuring voltage changes when an object is __.

present

The two configurations for driving relay coils are low-side and __ drive.

high-side

The purpose of a resistor-capacitor snubber is to mitigate the effects of __.

contact arcing