# Circuits Flashcards Preview

## Electricity & Magnetism > Circuits > Flashcards

Flashcards in Circuits Deck (20)
1
Q

Current exists whenever…

A

there is a net flow of charge (not an electrostatic equilibrium).

2
Q

DC Current from…

A

batteries.

3
Q

SI unit of current

A

Ampere

4
Q

By convention, the direction of current is…

A

The direction of the flow of positive charge.

5
Q

Charge carriers: Positive or negative?

A

Negative

6
Q

Current

A

The electrons in a conductor move in response to an electric field in the conductor.

7
Q

vd

A

drift speed.

8
Q

drift speed dependent on many parameters, most notably

A

temperature

9
Q

At a higher temperature, the drift speed…

A

decreases - more collisions.

10
Q

sigma

A

conductivity of metal.

11
Q

rho =

A

1/sigma

12
Q

Ohmic material

A

Resistance curve is linear.

13
Q

Kirchoff’s Rules for Circuits

A

Conservation of charge: junction rule. Conservation of energy: loop rule.

14
Q

Conservation of charge: junction rule

A

I in = I out (sums)

15
Q

Conservation of energy: loop rule

A

The sum of the potential differences across all the circuit elements in a closed loop must be zero.

16
Q

Power

A

Rate of energy transformation.

17
Q

Units of power

A

Watt

18
Q

Watt

A

Joules/Second

19
Q

Series

A

Two circuit elements are said to be connected in series if the current, passing through one, has no option but to pass through the other.

20
Q

Parallel

A

Two circuit elements are said to be connected in parallel if both their sides are connected with no intervening circuit elements.