9200541
Description
| Question | Answer |
| What is the current? | The flow of electric charge around the circuit. It will only flow through a component if there is potential difference across that component Unit = Ampere (A) |
| What is the Potential Difference? | The driving force that pushes the current round |
| What is the resistance? | anything in the circuit which slows the flow down |
| TRUE OR FALSE The greater the resistance across a component the smaller the current that flows | TRUE |
| What is the equation for current? | Current (I) = Charge (Q) / Time (t) |
| What is the equation for charge? | Charge (Q) = Current (I) x Time (t) |
| What is the equation for potential difference? | Potential Difference (V) = Work Done (W) / Charge (Q) |
| What symbol is this? | Resistor |
|
What symbol is this?
Image:
Thermistor (image/png)
|
Thermistor |
| What symbol is this? | Switch open |
|
What symbol is this?
Image:
Ldr 1 2 1 14 (image/gif)
|
Light dependent resistor |
|
What symbol is this?
Image:
Ammeter (image/png)
|
Ammeter |
|
What is this called
and what is it used for?
Image:
Test Circuit (image/gif)
|
The Standard Circuit This is the circuit you use if you want to know the resistance of a component. You find the resistance by measuring the current through and potential difference across the component. |
| Describe the role of the ammeter in the standard circuit | It measures the current (in amps) flowing through the component It must be placed in the series Can be put anywhere in the series in the main circuit but never parallel to the voltmeter |
| Describe the role of the voltmeter in the standard circuit | It measures the potential difference across the component. It must be placed parallel to the component. Not around battery or variable resistor |
| Explain how resistance increases with temperature | When an electrical charge flows through a resistor, some of the electrical energy is transferred into heat energy and the resistor gets hot. The heat energy causes the ions in the conductor to vibrate more. With the ions vibrating more it harder for charge carrying electrons to get through the resistor. The current can't flow as easily and the resistance increases. There is a limit to the amount of current that can flow. More current means an increase in temperature which means an increase in resistance which means the current decreases. |
| What is the equation for potential difference | P.D. (V) = Current (I) x Resistance (R) |
| Describe how this symbol works | A diode is a device made from a semi-conductor material such a silicon, it is used to regulate the potential difference in circuits. It lets current flow freely through it one direction but not in the other ( there is a high resistance in the reverse direction) |
| Describe how this symbol works | A light-emitting diode emits light when a current flows through it in the forward direction. They are being used more and more as lighting as they use a much smaller current than other forms of lighting. They indicate the presence of a current in the circuit. |
|
Describe how this symbol works
Image:
Ldr 1 2 1 14 (image/gif)
|
The light-dependent resistor is a resistor that is dependent on light. In bright light the resistance falls. In the dark it is at its highest. |
|
Describe how this symbol works
Image:
Thermistor (image/png)
|
A thermistor is a temperature dependent resistor. In hot conditions the resistance drops and in cool conditions the resistance rises. It is used for car engine temperature sensors. |
| Describe a series circuit | In a series circuit the different components are connected in a line, end to end, between the +ve and -ve of the power supply, (except for voltmeters which are connected in parallel, however they do not count as part of the circuit) If you remove one component the whole circuit will stop They are not very handy and in practice not many things are connected in series |
| Explain potential difference in a series circuit | The potential difference is shared between various components so the voltage round a series circuit always adds up to equal the source voltage |
| Explain the current in a series circuit | The same current flows through all parts of the circuit. The size depends on the potential difference and resistance I = V / R |
| Explain the resistance in a series circuit | The resistance adds up (R = R1 + R2 + R3) The bigger the resistance the bigger its share of potential difference |
| Explain cell voltage in a series cicuit | Cell voltage adds up |
| Describe a parallel circuit | In parallel circuits, each component is separately connected to the +ve and -ve of the supply If you remove or disconnect one of them, it will hardly effect the rest of the others. This is obviously how most things must be connected, for example in cars and in household electric. You have to switch everything off seperately |
| Explain potential difference in a parallel circuit | It is the same across all components V1 = V2 = V3 |
| Explain current in a parallel circuit | In parallel circuit the total current flowing around the circuit is equal to the total of all the currents through the separate components A = A1 + A2 + .... There are junctions where the current either splits or rejoins. The total current going into a junction has to equal the total current leaving. |
| Explain how Voltmeters and Ammeters are exceptions to the rules | Ammeters and Voltmeters are exceptions because ammeters are always connected in series even in a parallel circuit and voltmeters are always connected in parallel with a component even in a series circuit |
0 comments
Want to create your own Flashcards for free with GoConqr? Learn more.