MENG 447

Electrical Control

Components

Switches

•Mechanical

•Electrical

•OpticalElectromagnet

DC Motor

Integrated Device

Mechanical Switches On-Off, push button switches

Single Pole, Single Throw = SPST

A simple on-off switch. This type can be used to switch the power supply to a circuit.

Push-to-make = SPST Momentary

A push-to-make switch returns to its normally open (off) position when you release the button

Push-to-break = SPST Momentary

A push-to-break switch returns to its normally closed (on) position when you release the button.

Relay

The relay acts as a switch , pins 1 & 2 are used to supply the coil with power. Before energizing the relay, pins 3 & 5 are normally closed and pins 4 & 5 are normally opened.

After energizing the relay , pins 3 & 5 will be opened and pins 4 & 5 will be closed.

3

2

4

51

Electrical Switches

Photoconductive

The photoconductor cell acts like a switch. when a beam of light falls on it , it connects points A and B.

A

B

Optical Switches

The output stage component

It is a potentiometer which controls the sensitivity of the photoconductive cell.

Electromagnet

It is an electrical magnet which uses the electrical power to generate an magnetic field.

DC Motor

It’s a device converts an electrical power to mechanical power.

In this experiment we control a conveyor belt through the photoconductive cell.

When the beam of light falls on to the photoconductive cell, it closes the circuit, allowing current to flow in and operate the motor which

moves the belt. When the work piece on the belt cuts off the light beam, the belt stops moving.