3.5.1.5 Potential Dividers Flashcards
What is a potential divider?
A potential divider consists of two or more resistors in series with each and in series with a source of fixed potential difference.
The potential difference is divided between the components in series in the circuit, as they are in series with each other.
What are potential difference used for?
Potential dividers are used to supply a varying potential difference.
What can a potential divider be used for?
To supply a potential difference which is fixed at any value between zero and the source p.d.
To supply a variable potential difference.
To supply a potential difference that varies with physical condition such as temperature, pressure or light intensity.
How is the p.d. of the voltage source split?
It is split in the ration of the resistances.
This is because potential difference and resistance are directly proportion when current is constant in a series circuit.
What is the notation for potential dividers?
The voltage of the source = Vs Resistor 1 = R1 Resistor 2 = R2 Voltage of R1 = V1 Voltage of R2 = V2 Voltage output = Vout
What is the equation which shows that the ratio of resistances is equal to the ratio of the potential differences?
V1 / V2 = R1 / R2
What is the potential divider equation?
Vout = R2 / (R1 + R1) x Vs
R2 is always the resistance of which the voltage output is across.
How could you use a potential divider to supply a potential difference?
The source of potential difference is connected to a fixed length of uniform resistance wire.
A sliding contact can then be used on the wire to move the contact along the wire. This will give you a variable p.d. between the contact and one end of the wire.
A uniform track of a suitable material may be used instead of resistance wire.
How can a variable potential divider be used in a loudspeaker?
A simple audio volume control to change the loudness of a sound from a loudspeaker.
The audio signal potential difference is supplied to the potential divider in place of a cell or battery.
The variable output potential difference from the potential divider is supplied to the loudspeaker.
What is the effect of using a variable resistor in a potential divider circuit?
Replacing one of the resistors with a variable resistor would allow you to vary the voltage output (Vout).
What is a potentiometer?
A potentiometer has a variable resistor replacing R1 and R2 of the potential divider, but it uses the same ideas. As you move the slider down, the relative sizes of R1 and R2 increase and decrease to vary the voltage.
