# Systems 1 DC Circuits

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The flashcards below were created by user glennrooke on FreezingBlue Flashcards.

1. Resistance in relation to Temp, Length, and cross sectional area of the conductor.
• Proportional to Temp and Length
• Inversely proportional to Cross sectional area
2. State Ohms law
V = IR

Voltage = Amps x Resistance.
3. State both equations for Power
P = VI

P = IR
4. State Kirchoffs Law
I1  =   I2   +    I3
5. Primary and Secondary cells are also known as what?
Primary - non Rechargeable

Secondary - Rechargeable
6. In an Primary (Dry) Cell, what are the positive core, Negative case, and electrolyte made of?
Positive - Carbon

Negative - Zinc

Electrolyte - Ammonia Chloride paste
7. In an Secondary Cell, what are the positive core, Negative case, and electrolyte made of?

Dilute Sulphuric Acid
8. How many volts will a Lead Acid Cell produce?
2.1 volts max
9. How long is the standard discharge period when testing the capacity of batteries?
10 hours
10. How long should a voltmeter show the rated voltage of the battery when a test load is put in parallel if the battery is healthy?
Should show rated voltage for 15sec
11. What should the SG range be in a fully charged lead acid battery?

What will SG be when fully discharged?
Charged 1.25 - 1.30

Discharged 1.17
12. In an Alkaline NiCad Battery what are the positive and negative plates, and the Electrolyte made of?
Positive - Nickel Hydroxide

electrolyte - Distilled water and potassium Hydroxide
Smaller, Lighter, more Robust

Last Longer (more charge-discharge cycles)

Better performance at low temps

voltage remains constant through whole discharge cycle

Can be left fully discharged
14. How many volts per cell do Nicads produce?
1.2
Give off Oxygen and Hydrogen while being charged

Cant be left in a discharged state or lead sulphate coats the plates and stops charge being accepted
Low thermal capacity so prone to thermal runaway when being charged
17. When connecting batteries in Series, what happens to the rated capacity, and to the voltage
Rated Capacity remains the same

voltages are summed
18. When connecting batteries in Parallel, what happens to the rated capacity, and to the voltage
Rated Capacity is summed

Voltage remains same as for a single battery
19. How is the ground power relay powered from the 3 pin receptacle?
From the shorter of 3 pins so it cuts power before the other 2 longer pins come out and cause possible arcing
20. Name the 3 typical requirements of an aircraft electrical system
1) Supply to all equipment must be maintained unless total demand exceeds available supply

2) Systems faults should have the least possible effect on overall system functioning

3) A fault on one piece of equipment should not affect the power supply to the others
21. What are Vital consumers?
Services required in an emergency when all main power sources are lost. Emergency lighting, fire detection etc. Connected Directly to battery supply
22. What are essential consumers?
Necessary for safe flight in an emergency situation. Connected to bus bar than can be supplied by Gen or Batt
23. what are Non-Essential consumers?
Can be safely disconnected during in-flight emergency for purposes of load shedding. Supplied from the Gen bus
24. At what voltage will over-volt protections typically kick in with a 12v system?
16.5v
25. How many degrees of motion does a rotary actuator typically move through?
350o

fuel cocks, hydraulic rotary valves, butterfly valves etc
26. What is the active component of a circuit breaker, and what is a difference between "trip-free" and "non trip-free"
Bimetallic strip

Trip-free cant be held in to make the circuit
27. Static wicks are made of what
Carbon or Copper
28. What is the bonding component in conducting tyres
Carbon - normally only nosewheel
29. What re-fueling flow rate could produce static electricity
5000l/min or more.

In over wing refueling nozzle must touch airframe as fuel exciting can cause spark.

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 Author: glennrooke ID: 227127 Filename: Systems 1 DC Circuits Updated: 2013-07-16 01:38:09 Tags: DC Circuits Folders: Description: DC Circuits Show Answers:

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