"Rheostats" Voltage Resistance PPT Courseware 2

Description

"Rheostats" Voltage Resistance PPT Courseware 2

Thinking questions (1)

How do desk lamps and radios change their brightness and volume?

Changing the number of battery cells can change the brightness of the bulb, but the brightness cannot be adjusted continuously. What should I do?

To make the brightness of the light bulb continuously adjustable, please try using the equipment around you. Is it the easiest way to do it?

Think about it, do it

How does the brightness of the small light bulb change when the wire clip is moved along the pencil lead?

Why do you think the brightness of the light bulb changes like this?

Experiment summary

Phenomenon:

As the length of the pencil lead connected to the circuit becomes longer, the current represents the number ____ and the brightness of the light bulb ____.

When the length of the pencil lead connected to the circuit becomes shorter, the current is expressed as ____ and the light bulb becomes brighter ____.

Thinking questions (2)

What caused the current change in this experiment?

What are the disadvantages of using a pen tip to change the resistance in the circuit?

The principle and function of varistor

effect:

Changing the size of the current by changing the size of the resistor

principle:

Change the resistance by changing the length of the resistance wire in the circuit

How to use sliding rheostat

(1) Generally, they should be connected in series in the circuit

(2) Match one up and one down, mainly look at the bottom (the sliding resistance becomes larger toward the lower binding post, and the sliding resistance becomes smaller away from the lower binding post)

(3) The slider should be placed at the maximum resistance position before use.

what did you learn

1. Sliding rheostat

1. Principle: Change the length of the resistance line in the access circuit, thereby changing the resistance in the access circuit.

2. Structure:

3. Structural diagram:

4. Component symbols

5. Connection method:

(1) Series access circuit;

(2) Connect the two terminals "one up and one down".

6. Things to note:

(1) Before closing the switch, the slider should be placed at the maximum resistance end.

(2) The maximum current allowed by the sliding rheostat cannot be exceeded

2. Resistor box

practice

1. Among the four connection methods of the sliding rheostat as shown in the figure, when the slider P of the rheostat moves to the left, the current in the circuit will increase ( )

(A) A and B (B) C and D

(C) A and C (D) A and D

2. The nameplate of a sliding rheostat is marked with "20Ω 1A", which means ( ) of the rheostat

(A) The minimum value of the resistance is 20Ω, and the maximum current allowed to pass is 1A

(B) The minimum resistance value is 20Ω, and the minimum current allowed to pass is 1A

(C) The maximum resistance value is 20Ω, and the minimum current allowed to pass is 1A

(D) The resistance range is 0-20Ω, and the maximum current allowed to pass is 1A

Class summary

1. A component that can change the resistance of an access circuit is called a rheostat.

2. The sliding rheostat changes the access resistance by changing the length of the resistance line in the access circuit, thereby changing the current. It should be connected in series in the circuit, and the wiring should be "one up and one down".

3. Potentiometer is the application of rheostat in daily life.

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For more information about the "Rheistor Voltage Resistance" PPT courseware, please click on the Rheostat ppt Voltage Resistance ppt tag.

"Rheostats" PPT download:

"Rheistor" PPT download Part 1: Knowledge review 1. What physical quantity is resistance? Answer: Resistance is a physical quantity that represents the resistance of a conductor to current; the greater the resistance, the greater the resistance to current. 2. The factors that affect the size of the resistance are...

"Rheostats" PPT courseware:

"Rheistor" PPT courseware part one content: Rheostat 1. Rheostat: Principle of a device used to change the resistance: the size of the resistance changes with the length of the conductor. The maximum resistance value of this sliding varistor is 20, and the maximum current allowed is 2A. ..

"Rheostats" PPT:

"Rheistor" PPT Part One Content: Review Resistance (symbol: R) 1. Concept: The obstruction effect of conductors on current flow. The more resistant a conductor is to the flow of electricity, the greater its resistance. 2. Unit: ohm (ohm) (symbol: ) kiloohm (K), megaohm..

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Update Time: 2024-10-03

This template belongs to Physics courseware People's Education Edition Ninth Grade Physics Complete Book industry PPT template

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