# P6

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What is a potential divider?
A potential divider is a pair od resistors which divide the voltage of a circuit so you can get outputs of different voltages
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What is the formula for a potential divider?
Formula
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What is the formula for resistors in series and in parallel
formula
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Explain the three main parts of a Transistor
BASE controls the flow of current. small current can allow more current from collector and emitter. COLLECTOR where current flows in, EMITTER where current flows out.
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What is the formula for the emitted current in a transistor?
Current of Emitter = Current of Collector + Current of Base
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What are AND logic gates made from and how do they work
Two transistors, if no current flows then the base of either transistor will not allow any current to flow, meaning the only output 1 for AND gates are inputs 1 and 1
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How does a relay work?
diagram
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Draw a diagram of a relay
When the switch in low current circuit is closed, it turns on the electromagnet which attracts the iron contact on the rocker, iron pulls pivot and closes contact with high coltage, the motor spins. opening the low voltage circuit closes the circuits
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3 ways to increase the strength of a solenoid?
More current, More coils, soft iron core
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Draw a diagram of a simple electric motor
diagram
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4 factors which speed up a motor
more current, more turn on the coil, stronger magnetic field, soft iron core in the coil
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What does the split ring commutator do in an electric motor?
Swaps the contacts every half turn the keep the motor rotating in the same directon
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How do you reverse the direction of the motor?
Swap the polarity of the DC supply or swap the magnetic poles over
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how would you increase the efficiency of a motor?
Make the poles more curved so they form a hollow cylinder, meaning there is a radial magnetic field, which increase
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What is electromagnetic induction?
Electromagnetic induction is the creation of voltage in a wire experiencing a change in magnetic field
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What four factors affect the size of the induced voltage from electromagnetic induction?
Strength of the magnet, Area of the coil, Number of turns on the coil, the speed of movement
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Give 4 examples of electromagnetic induction
Moving a magnet side to side in a long coil, moving a rectangular coil through a magnetic field, moving a long coil into a horseshoe magnet, rotating a magnet in the middle of a coil.
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What type of current does electromagnetic induction form and why?
electromagnetic induction produces an AC current, because for half the spin the current is increasing in one direction, and for the other half it is increasing in the other direction (Due to the two different magnetic poles)
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What do generators use instead of split-ring commutator and why?
They use slip rings and brushes so the contacts DON'T swap every half turn, so it produces an AC current
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What is the equation for power loss?
Power loss = Current (Squared) X Resistance
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## Other cards in this set

### Card 2

#### Front

What is the formula for a potential divider?

Formula

### Card 3

#### Front

What is the formula for resistors in series and in parallel

### Card 4

#### Front

Explain the three main parts of a Transistor

### Card 5

#### Front

What is the formula for the emitted current in a transistor?