Ohms Law

“Ohm’s Law deals with the relationship between voltage and current in an ideal conductor”

Lets focus on three words in definition

1) Voltage

2) Current

3) Conductor

4) Ideal

Formula

So to see the formula let’s say we have a source battery connected with a load resistor.

OHMS LAW TRIANGLE

An easy way to remember formulas

Ohms Law Problem 1

For the following circuit , find the current

Solution

Given

E=12 V

R=3 Ohm

Find

I

Formula

I=E/R

Ohms Law Problem 2

For the following circuit find the resistance of R

Measuring Devices

Voltmeter is a device that is used to measure voltage or potential difference. Volt meter can be digital , where the answer is shown in digits, or analogue, where a deflecting image shows the value

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Ammeter

An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name. Instruments used to measure smaller currents, in the milliampere or microampere range, are designated as milliammeters or microammeters.

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Difference Between Ammeters And Voltmeters:

Parameters	Ammeter	Voltmeter
Connection	It is to be connected in series mode	It is to be connected in parallel mode
Resistance	It has comparatively low resistance	It has high resistance
Uses	It is used to find the amount of current flowing in the circuit	It is used to find the potential difference in the circuit
Circuit	Circuit must be disconnected in order to attach the ammeter	Circuit does not need to be disconnected
Accuracy	Considered as less accurate	Considered as more accurate compared to ammeter

Ammeter and Voltmeter Connections

Resistors

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits

The resistor’s ability to reduce the current is called resistance and is measured in units of ohms (symbol: Ω).

Colour Coding

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