3.7 Resistors

Question 1

Name the tolerance bands and their values

Answer 1

Brown 1%, Red 2% Gold 5%, Silver 10%, None 20%

Question 2

If 2 resistors in parallel are of the same value?

Answer 2

The resistors when joined together to make 1 will be of the value which is half that? eg: 2 resistors in parallel of 10 ohms will equal 1 at 5.

Question 3

How many circuit connections are there on a potentiometer?

Answer 3

3 contacts or terminals

Question 4

Potentiometer are?

Answer 4

high resistance devices so minimum current is drawn but the voltage is variable between min and max.

Question 5

How many circuit connections are there on a rheostat?

Answer 5

2, fixed contact at one end and a sliding contact that can be moved along the resistance element.

Question 6

What is the basic principle of a rheostat,

Answer 6

The sliding contact moves towards or away from the fixed contact lengthening or shortening the resistance band which in turn increases or decreases current.

Question 7

Rheostats are

Answer 7

High current low resistance devices.

Question 8

What is the purpose of the wheatstone bridge?

Answer 8

do measure resistance and precisely compare resistance.

Question 9

Positive temperature coeficient

Answer 9

resistance increases with an increase in temperature

Question 10

Negative temperature coefficient

Answer 10

resistance decreases with an increase in temperature

Question 11

Zero temperature coefficient

Answer 11

No resistance change with temp change.

Question 12

In a carbon composition resistor how is the ohmic value achieved? and what is a disadvantage of them.

Answer 12

Filler is mixed with carbon material. the resistance depends on the carbon to clay ratio, they tend to generate noise as they age.