26 lines
1.2 KiB
Markdown
26 lines
1.2 KiB
Markdown
# ECE 140: Linear Circuits
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## Voltage, current, and resistance
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Please see [SL Physics 1#Electric potential](/g11/sph3u7#electric-potential) for more information on voltage.
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Please see [SL Physics 1#5.2 - Heating effect of electric currents](/g11/sph3u7/#52-heating-effect-of-electric-currents) for more information on current.
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Please see [SL Physics 1#Resistance](/g11/sph3u7/#resistance) for more information on resistance.
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**Electric charge** $Q$ quantises the charge of electrons and positive ions, and is expressed in coulombs (**C**).
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Objects with charge generate electric fields, thus granting potential energy that is released upon proximity to another charge.
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!!! warning
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Voltage and current are capitalised in **direct current only** ($V$, $I$). In general use, their lowercase forms should be used instead ($v, $i$).
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**Voltage** is related to the change in energy ($dw$) over the change in charge ($dq$), or alternatively through Ohm's law:
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$$i=\frac{dw}{dq}=\frac{i}{R}$$
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**Current** represents the rate of flow of charge in amps (**A**). Conventional current moves opposite electron flow because old scientists couldn't figure it out properly.
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$$i=\frac{dq}{dt}\approx \frac{\Delta q}{\Delta t}$$
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