# data[].attributes.headline
Effects of a Force on the Motion of a Body

# data[].attributes.subject
Effects of a Force on the Motion of a Body

# data[].attributes.body
draw circuit diagrams with power sources (cell, battery, d.c. supply or a.c. supply), switches, lamps, resistors (fixed and variable), variable potential divider (potentiometer), fuses, ammeters and voltmeters, bells, light-dependent resistors, thermistors and light-emitting diodes

# data[].attributes.body
state that the current at every point in a series circuit is the same and apply the principle to new situations or to solve related problems

state that the sum of the potential differences in a series circuit is equal to the potential difference across the whole circuit and apply the principle to new situations or to solve related problems

# data[].attributes.body
state that the current from the source is the sum of the currents in the separate branches of a parallel circuit and apply the principle to new situations or to solve related problems

state that the potential difference across the separate branches of a parallel circuit is the same and apply the principle to new situations or to solve related problems

# data[].attributes.body
recall and apply the formulae for the effective resistance of a number of resistors in series and in parallel to new situations or to solve related problems

recall and apply the relevant relationships, including R = V / I and those for current, potential differences and resistors in series and in parallel circuits, in calculations involving a whole circuit

# data[].attributes.body
describe the action of a variable potential divider (potentiometer)

# data[].attributes.body
describe the action of negative temperature coefficient (NTC) thermistors and light-dependent resistors and explain their use as input transducers in potential dividers

solve simple circuit problems involving NTC thermistors and light-dependent resistors.

# data[].attributes.body
the sum of individual currents in each of the branches is equal to the main current.

I ε = I ₁ + I ₂ + I ₃ + … + I n

the potential difference across each branch is equal to the potential difference across the whole circuit.

Vε = V₁ = V₂

In a parallel circuit, the effective resistance is always smaller than the smallest individual resistance.

# data[].attributes.body
the current at every point is the same;

the sum of the potential difference across each component is equal to the potential difference across the whole circuit.

Vε = V ₁ + V ₂ + V ₃ + … + V n

RT = R₁ + R₂ + . . . + Rn

# data[].attributes.body
In a series circuit, the effective resistance is always greater than the largest of the individual resistances.

# data[].attributes.headline
Example 17.2.1: The circuit shows a 10 Ω resistor and a 20 Ω resistor connected in parallel to a 6 V cell of negligible internal resistance. Calculate the currents I1, I2 and I3. 

# data[].attributes.subject
Example 17.2.1: The circuit shows a 10 Ω resistor and a 20 Ω resistor connected in parallel to a 6 V cell of negligible internal resistance. Calculate the currents I1, I2 and I3. 

# data[].attributes.headline
A potential divider is a line of resistors connected in series. It is used to provide a fraction of the voltage of a source to another part of the circuit.

# data[].attributes.subject
A potential divider is a line of resistors connected in series. It is used to provide a fraction of the voltage of a source to another part of the circuit.

# data[].attributes.body
As we have seen, we can vary the value of V out by changing the resistance of the resistors R1 and R2..

To do this, we can change the fixed resistors, or we can make use of variable resistors.

# data[].attributes.attachment_link.title
07 potentiometer according to IGCSE - GCSE physics syllabus, electric current

# data[].attributes.body
The circuit shows a 9 V battery connected in series with a variable resistor R1 and a 50 Ω resistor R2. The resistance of the variable resistor R1 can vary from 0 to 100 Ω. What are the maximum and minimum output voltages?

# data[].attributes.body
Transducers are electronic devices that convert energy from one form to another.

They are two types: input transducers and output transducers.

Input transducers are electronic devices that respond to changes in the physical environment.

They can be used in potential dividers to vary output voltages.

Therefore, they allow electronic devices to respond to changes in the environment.

Input transducers are electronic devices that convert non-electrical energy to electrical energy.

# data[].attributes.body
•   A thermistor is a device whose resistance varies with temperature.

•   Negative temperature coefficient (NTC) vs positive temperature coefficient (PTC)

•   In the circuit shown on the right, when the resistance of the common resistor R TH decreases, V out increases.

•   Thermistors can be used for temperature control and measurement.

# data[].attributes.attachment_link.title
Basics of NTC and PTC Thermistors - Another Teaching Moment | Digi-Key Electronics

# data[].attributes.headline
Input Transducers —  Light-Dependent Resistors (LDRs)

# data[].attributes.subject
Input Transducers —  Light-Dependent Resistors (LDRs)

# data[].attributes.body
•  The resistance R LDR of a light-dependent resistor decreases with increasing light intensity.

•  In the circuit shown on the right, when R LDR decreases, V out increases.

•  LDRs can be used in devices that measure light intensity and in automatic street lights.

# data[].attributes.body
As light intensity decreases, R LDR increases, and the voltmeter reading also increases.

The circuit can be used in street lamps that turn on automatically when it gets dark in the evening by connecting the output of the LDR to a switch connected to the street lamp.