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22 Cards in this Set
- Front
- Back
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VOLTMETER |
---------(v)---------- |
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AMMETER |
--------(A)--------
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OHMMETER |
--------( _n_ )--------- |
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DIODE |
---------( >| )---------- |
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LED |
^^ ----------( >| )---------- |
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LDR |
------------( = )------------ |
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FIXED RESISTOR |
______ -----------|_____|----------- |
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VARIABLE RESISTOR |
^ __ /___ ---------|__/___|--------- |
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FILAMENT BULB |
---------(X)--------- |
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THERMISTOR |
___ /___ --------|__ /___|-------- __/ |
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What is current? |
Current is the rate of flow of charge |
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What is charge? |
Electrons are considered to be grouped in packs of charge called coulombs |
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What is resistance? |
This is a measure of how difficult it is for current to flow. It is measured using an ohmmeter |
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What is voltage? |
Also known as potential difference, voltage is the amount of energy per unit of charge. It is measured with a voltmeter |
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What is the National Grid? |
The electricity that reaches our house and businesses is through a network of wires and transformers known as the national grid |
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What is a step-up transformer? |
These increase the voltage to 132000V and decrease the current to reduce the heating effect and more the system more energy efficient |
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What is a step-down transformer? |
These reduce the voltage back down to safe levels |
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Rules for current in circuits: |
The current going into a point is the same as the current coming out of that point. eg /5 8 ---- >----- * \3 |
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Rules for PD in circuits: |
The amount of energy provided / electron from a battery= the total amount of energy transferred in one loop (bakery truck method) |
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Rules for resistance in circuits: |
In a series, the total resistance is the sum of the individual resistors. In a parallel the total resistance is less than any of the individual resistors. |
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what is direct current? |
Current flows in one direction only. On an oscilloscope trace, the trace will all be positive voltage or all negative voltage |
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What is alternating current? |
The direction of the current is continually changing direction, on an oscilloscope trace, the line will be in both positive and negative regions |
