Electriciry Flashcards
Current
The flow of Charge around a circuit
One coulomb
Amount of charge that passes in second if the current is 1A
Potential difference
Work done per unit charge moved
Volt
The potential difference across a component is 1 volt when you convert 1J of energy moving 1 C of charge through the component
Thermistor
Resistance decreases as temperature goes up as more free electrons become available to carry current
What is is the gradient equal to
R/l = p/A so multiply gradient by cross sectional area
Critical temperature for superconductors
Below 10K (-263C)
Uses of superconductors
Power cables
Strong electromagnets (maglev trains and medical application)
Electronic circuits
Ohms law
The pd across a metallic conductor is proportional to the current flowing through it, provided the conditions don’t change
Threshold voltage
0.6V, voltage in semiconducting diode needed in order to conduct
Power
The rate of transfer of energy
Kirchoffs first law
The algebraic sum of curren at a junction is zero
Kirchoffs 2nd law
Around any closed loop in a circuit the sum of EMFs is equal to the sum of pd
