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Electronics - Circuits:
What does it mean if two lights are "in series"?
How does the current going through them compare to the current being supplied by the battery?
- It means that they are one after each other in a straight line.
- The current going through both is the same as the current being supplied by the battery.
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Electronics - Circuits:
What does it mean if two lights are "in parallel" in a circuit? If there were three lights in parallel, how would the current going through each compare to the current being supplied by the battery?
In parallel means that they appear in a parallel in a circuit.
If three lights were in parallel, the current going though them would be 1/3rd of the current being supplied by the battery.
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Electronics - Circuits:
Are the lights in series or in parallel?
In series (current is the same throughout).
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Electronics - Circuits:
Are the lights in series or in parallel?
- In parallel.
- Here, the current from the battery gets split into three. Each of the lights gets the same current through it, but this current is only 1/3rd of the current a bulb in a series circuit would get.
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Electronics - Switches:
Draw the symbol for a "push to make" switch and describe what it does.
- It MAKES the circuit when pressed down.
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Electronics - Switches:
Draw the symbol for a "push to break" switch and describe what it does.
- when pushed it BREAKS the circuit
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Electronics - Switches:
Draw the symbol for a "reed" switch and describe what it does.
- when a magnet comes near, the reed wires are forced together to make the circuit.
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Electronics - Switches:
Draw the symbol for a "On/off" switch and give another name for it.
- another name is : SPST switch
- (single pole, single throw)
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Electronics - Switches:
Draw the symbol for a "2 way" switch and give another name for it.
- another name is SPDT switch.
- (single pole, double throw)
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Electronics - LEDs:
What does LED stand for?
Light Emitting Diode
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Electronics - LEDs:
When including an LED in any circuit, what must you remember to include, and why?
To put a resistor in front of it in the circuit. This is because LEDs only need a tiny amount of current (max 30mA) and the resistor will dramatically reduce the current going into the LED so it doesn't burn out. LEDs typically operate between 10-20mA of current.
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Electronics - LEDs:
What are the two legs of an LED called and which one is postive / negative?
- Anode - negative (think of anti)
- Cathode - positive (this leg is longer than the anode)
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Electronics - LEDs:
What is the safe operating voltage of an LED?
1.5 volts up to 5 volts
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Electronics - LEDs:
What way should a LED be connected to a battery (postive / negative)?
The negative ANODE should be connected to the POSTIVE BATTERY terminal.
The positive CATHODE should be connected to the NEGATIVE BATTERY terminal.
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Electronic - Circuit Calculations:
What is the formula relating voltage, current and resistance? What are the units of each?
- V = I . R
- V is voltage and is in VOLTS
- I is current and is in AMPS
- R is resistance and is in OHMS
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Electronic - Circuit Calculation:
If a circuit has a 9V battery and the resistor is 200ohms, will the LED work ok (show why)?
No the LED will burn out, because the current going though it will be too high.
- Using V = I.R
- I (current) would be 9/200 = 0.045A = 45mA. Most LEDs will burn out at above 30mA.
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