What is SPDT switch?
SPDT stands for Single Pole Double Throw. It is a type of switch that has three terminals: one common terminal and two separate terminals (often referred to as A and B terminals). The common terminal is connected to one of the other terminals (A or B) when the switch is in the “on” position, and to the other terminal when the switch is in the “off” position. SPDT switches are commonly used in electronics and electrical engineering applications, such as in circuit switching and routing.
PRACTICE Assignments on SPDT switches
Assignment 1:-
The lamp is OFF when the switch S1 is ON. The lamp should remain OFF even if switch S1 is OFF. (Hints:-Addressing of different contacts to the same switch)
Assignment 2:-
The lamp is ON when the switch S1 is ON. The lamp should remain ON even though the switch S1 is OFF. (Hints:-Addressing of different contacts to the same switch)
Assignment 3:-
a) When any of the two toggle switches are ON output will be OFF.
b) When any of the two toggle switches are OFF output will be OFF.
c) When both of the two toggle switches are ON output will be ON.
d) When both of the two toggle switches are OFF output will be ON.
Assignment 4:-
In a two-storied building, there are two two-way switches in the staircase. Write a suitable plc program such that when anyone makes either switch 1 or switch 2 ON or OFF the lamp in the staircase should glow and dark accordingly. The common lamp in between switch 1 and switch 2 can be made ON or OFF by the two switches. The lamp can be made ON by switch 1 and can be made OFF by switch 2 and can be made ON by switch 2 and OFF by switch 1.
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Assignment 5:-
In a corridor, there are four switches and three bulbs. When a man enters from one side of the corridor and presses switch 1, bulb 1 gets on. When the man presses switch 2, bulb 2 gets on and bulb1 gets off. When the man presses switch 3, bulb 3 gets on and bulb2 gets off. When the man presses switch 4, bulb 3 gets off.
The same thing can happen if at any instance a man enters from any side.
Assignment 6:-
A railway tunnel is equipped with 10-halogen lamps at an equal distance so as to ensure light to the engine driver. The
lights are activated by 11 toggle switches fitted on the tracks. As the train enters the tunnel irrespective of the direction, the lamps will be made ON one after another when the switches are activated. (Only one lamp is ON at any
point in time when there is a train in the tunnel) When the train leaves the tunnel, all the lamps will be OFF.
Assignment 7:-
Design a ladder network for a car door glass control system. The door glasses can be controlled by any of the passengers or by the car driver. Individual passengers can also control the door glass separately. If no passenger is inside the car, the driver can make all the door glass open and close from his seat. When all the door glass is closed then only AC can be started inside the car. When AC is running if any door glass is opened by either any passenger or by the driver then AC should get OFF automatically.
Assignment 8:
Design a circuit using SPDT switch which will turn on a light when the switch is in one position and turn on a buzzer when the switch is in the other position.
Hints: You can use a relay to control the light and the buzzer.
Assignment 9:
Design a circuit using two SPDT switches which will control a motor. The motor should turn on when both switches are in the same position and turn off when the switches are in different positions.
Hints: You can use a relay to control the motor.
Assignment 10:
Design a circuit using an SPDT switch which will control the direction of a motor. When the switch is in one position, the motor should turn clockwise and when the switch is in the other position, the motor should turn counterclockwise.
Hints: You can use a motor driver circuit to control the direction of the motor.
Assignment 11:
Design a circuit using an SPDT switch which will control the speed of a motor. When the switch is in one position, the motor should run at a high speed and when the switch is in the other position, the motor should run at a low speed.
Hints: You can use a variable frequency drive to control the speed of the motor.
Assignment 12:
Design a circuit using two SPDT switches which will control a solenoid valve. When one switch is in one position and the other switch is in the opposite position, the solenoid valve should open. When both switches are in the same position, the solenoid valve should close.
Hints: You can use a relay to control the solenoid valve.
Assignment 13:
Design a circuit using an SPDT switch which will control the heating and cooling system of a room. When the switch is in one position, the heating system should turn on and when the switch is in the other position, the cooling system should turn on.
Hints: You can use a relay to control the heating and cooling system.
Assignment 14:
Design a circuit using two SPDT switches which will control the speed and direction of a motor. When one switch is in one position, the motor should turn clockwise at a high speed and when the other switch is in the other position, the motor should turn counterclockwise at a low speed.
Hints: You can use a motor driver circuit to control the speed and direction of the motor.
Assignment 15:
Design a circuit using an SPDT switch which will control the lighting system of a room. When the switch is in one position, the main light should turn on and when the switch is in the other position, the dim light should turn on.
Hints: You can use a relay to control the main light and the dim light.
Assignment 16:
Design a circuit using two SPDT switches which will control a hydraulic cylinder. When one switch is in one position, the cylinder should extend and when the other switch is in the other position, the cylinder should retract.
Hints: You can use a solenoid valve to control the hydraulic cylinder.
Assignment 17:
Design a circuit using an SPDT switch that will control a water pump. When the switch is in one position, the pump should turn on and when the switch is in the other position, the pump should turn off.
Hints: You can use a relay to control the water pump.
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