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Current and Circuits - Coggle Diagram
Current and Circuits
Electric Change
Types of charges: Positive and Negative
Conservation of charge
Elementary charge 𝑒 = 1.60 × 10 − 19C
e=1.60×10 −19C
Unit: Coloumb
Electromotive Force
Unit: Volts
Formula: e=V+Ir
Definition: Work done to move a unit charge from one terminal to another in a circut
Potential/Voltage Divider
Simple, linear passive circuit that produces and output voltage which is a fraction of its input voltage, typically using two resistors in a series.
Two resistors connected in a series
Same current flows through every resistor.
As the same current passes through both resistors, the input voltage is distributed proportional to the resistance values (Kirchhoff’s law).
Potential drop across each resistor is proportional to its resistance.
V(out) = V(in) x R2/(R1+R2)
One resistor has to be constant while the other can be a thermistor meaning that is dependent on temperature.
Basic setup:
A cell or power supply
Two (or more) resistors in series
Output voltage taken across one resistor
Current
Fomrula: I= Q/t and V/r=I
Unit: Ampheres
Resistance
Resistance
Fomrula: V/I= r
Factors influencing resistance: length, cross-sectional area, resistivity, temprature
Formula: R= rho x L/A
Unit: Ohm
Internal Resistance
V=ε−Ir
Short-Circuit Current
Circuts
Series
Voltage is shared
R(total)= R1+R2
Current flows through every single component
Parallel
1/R(total)=1/R1+1/R2......
Has multiple branches
Current flows through each component independantly
Adding more resistors decreases resistances as there are more paths for current to flow