internal and combined resistance Flashcards
1
Q
what is resistance?
A
the main function of resistors in a circuit is to control the flow of current to to other components
measured in ohms
2
Q
calculation for resistance?
A
resistance = voltage/current
R=VI
3
Q
plotting VI graphs for a resistor?
A
- if the graph is curved, the resistance is not constant, therefore it id a non-ohmic device
- if the graph is a straight line the resistor is an ohmic device
4
Q
how to find out resistance in a series circuit?
A
the resistance values can just be added together
5
Q
how to find out the resistance in a parallel circuit?
A
1/R1 + 1/R2 = total resistance etc
6
Q
what does Kirchhoff’s first law state?
A
the sum of the current leaving any junction is always equal to the sum of the current that entered it
7
Q
what does Kirchhoff’s second law state?
A
the total voltage across a circuit loop is equal to the sum of the voltage across the devices in that loop
