# Yr8 Tech Electronics.txt

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1. 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, but the voltage is divided by the number of lights.
2. 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. But note that the voltage is the same through all three lights.
3. Electronics - Circuits:
Are the lights in series or in parallel?
In series (current is the same throughout, but voltage is shared).
4. 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. Note that the voltage is the same throughout.
5. Electronics - Switches:
Draw the symbol for a "push to make" switch and describe what it does.
• It MAKES the circuit when pressed down.
6. Electronics - Switches:
Draw the symbol for a "push to break" switch and describe what it does.
• when pushed it BREAKS the circuit
7. 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.
8. 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)
9. 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)
10. Electronics - LEDs:
What does LED stand for?
Light Emitting Diode
11. 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.
12. 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)
13. Electronics - LEDs:
What is the safe operating voltage of an LED?
1.5 volts up to 5 volts
14. 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.
15. 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
16. 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.
 Author: DC11 ID: 240582 Card Set: Yr8 Tech Electronics.txt Updated: 2013-10-14 20:42:25 Tags: Yr8 Tech Electronics Folders: Description: Yr8 Tech Electronics Show Answers: