- What do we use circuit symbols to show?
- What is the difference between series and parallel circuits?
- To show the different components of a circuit
- Series use one single loop, whereas Parallel use more than one loop.
- What are charged particles known as?
- What is the units of charge?
- A charged particle is an electron
- The units on charge is Coulombs (C)
- What is current?
- What is the units of current?
- Current is the rate of flow of charge (how much charge flows every second)
- Current has the unit amps (A) and is measured by an ammeter (which goes in series)
What equation links charge, current and time?
Q = I X t
I = Q / t
t = Q / I
I = Current (Amps, A)
Q = Charge (Coulombs, C)
t = Time (s)
What are the circuit symbols?
Look up, (photo in camera roll, downloads/ online)
What is potential difference?
Potential difference (also known as voltage) is a measure of how much energy is transferred to (or by) each coulomb of charge.
What is the units of potential difference and how is it measured?
Potential difference has the units of volts and is measured by a voltmeter (which goes in parallel)
What equation is used to find energy transferred?
E = V X Q
V = E / Q
Q = E / V
E = Energy (Joules, J)
Q = Charge (Coulombs, C)
V = Voltage (Volts, V)
- What is resistance?
- What does a higher resistance mean?
- Resistance is a measure of how hard it is for the current to pass through a component in a circuit.
- A higher resistance means it is harder for the current to pass through the component. (Higher = Harder)
What does Ohm’s law state?
That the current in a resistor is proportional to the potential difference. (Provided the temperature is at a constant)
What is the equation to find resistance?
R = V / I
V = I X R
I = V / R
I = Current (Amps, A)
V = Voltage (Volts, V)
R = Resistance (Ohms, Ω)
What is the relationship between volts and current?
As volts decreases, current decreases, and vice-versa
What is the power of an appliance?
The energy transferred to an appliance each second
What is the formula to find power?
P = E / T
E = P X T
T = P / E
P = Power (Watts, W)
E = Energy (Joules, J)
T = Time (seconds, s)
- In a series circuit the current flows through ___ continuous path. This means that the current must be ___ ___ at all parts in a series circuit.
- How does this compare to a parallel circuit?
- In a series circuit the current flow through one continuous path. This means they the current must be the same at all parts in a series circuit.
- In a parallel circuit, they are multiple paths the current can take, this mean the current splits and the current wont be the same at all parts of a parallel circuit.
In a series circuit, what is the relationship between the voltage supplied by the battery and the potential difference across the components?
The sum of the potential difference across the components equals the battery voltage.
In a series circuit, what is the relationship between the voltage supplied by the battery and the potential difference across the bulbs?
The sum of the potential difference across the battery is the same as the potential difference (voltage) across each bulb.
- As the temperature increases, what happens to the resistance of a thermistor?
- As light intensity increases, what happens to the resistance of an LDR?
- As temperature increases, the resistance of a thermistor decreases.
- As the light intensity increases, the resistance of an LDR decreases.
What are sensing circuits used in?
Sensing circuits are used in central heating that turns on when its cold, lights that turn on when its dark, or automatically opening doors.
- If an appliance has a metal casing, what does it need? Why?
- If an appliance has plastic casing, does it need this? What is the name for it?
- An appliance with metal casing needs an earth wire for safety.
- If an appliance has plastic casing, it doesn’t need an earth wire, it is known as double insulated.
- What is the correct size of fuse for an appliance?
- What is the largest domestic fuse size? What appliances is it reserved for?
- The correct size of fuse is one that is slightly above the regular operating current.
- The largest domestic fuse size is BA, it is reserved for high power devices such as electric radiators.
What is a circuit breaker?
A circuit breaker is a resettable switch that trips if too large a current flows.
- ___ ___ (D.C) only flows in ___ direction.
- ___ ___ (A.C) constantly changes direction.
- Direct Current (D.C) only flows in one direction
- Alternating Current (A.C) constantly changes direction
What voltage and hertz is Mains electricity, is it AC or DC?
Mains electricity flows at 230 Volts, and 50 Hertz, it is AC.
