Ohm’s law states that Resistance in ohms = Current in amps / EMF in volts Currents in amps = EMF in volts / Resistance in ohms EMF in volts = Resistance in ohms / Current in amps.
Which formula below is correct EMF in volts = Power in watts / Current in amps Power in watts = Current in amps / EMF in volts
EMF in volts = Current in amps / Power in watts.
The symbol for volts is I V R.
Electromotive force is measured in Watts Ohms Volts.
The current flowing in an electrical circuit is measured in Ohms Watts Amperes.
An electrical motor using 60 watts at 7.5 amps would have a voltage supply of 8 Volts 6 Volts 12 Volts.
The total resistance of several power consumer devices connected in series is The addition of the reciprocals of the individual resistances The addition of the individual resistances The reciprocal of the total the resistances.
The power supply for a DC series circuit is a 12-volt battery. There are three electrical devices each providing a resistance of 2 ohms. What is the current flow throughout the circuit? 6 Amps 3 Amps 2 Amps.
How much power is required in a circuit maintaining a current flow of 8 amps, with a circuit resistance of 10 ohms 800 watts 640 watts 400 watts.
What is the total voltage drop in a DC series circuit in which the applied voltage is 30 volts, and there are two resistors causing 5 ohms and 10 ohms resistance respectively 2 Volts 15 Volts 30 Volts.
In a simple DC circuit, if the power consuming devices are in parallel, the total current consumed is equal to The sum of the current taken by the devices divided by the number of the devices The sum of the reciprocals of the current taken by the devices The sum of the currents taken by the devices.
If a number of electrical devices are connected in parallel, their total resistance is The sum of their resistances The sum of he currents The sum of the resistance reciprocal.
Four electrical devices are connected in a parallel circuit, supplied by a six volt battery. The four devices respective resistance 15 ohms,60 ohms,12 ohms and 30 ohms. What is the total current flow 2.4 amps 1.8 amps 1.2 amps.
Power is equal to EMF . current Current + Resistance Current . Resistance.
Field windings are wound around the Yoke Pole pieces Armature.
The field windings of a shunt wound generator has Many turns of thin wire A few turn of thick wire Turns of thick and thin wire.
The output of a DC generator before commutation is DC AC Pulsated DC.
A shunt wound generator produces an electrical current in which Voltage increases with increase in load Voltage decreases slightly with increase in load Voltage remains constant with increase in load
.
In a shunt wound electrical generator as the load is increased Voltage falls off gradually Voltage falls off rapidly Voltage rises rapidly.
On a multi-engine aircraft which has one generator per engine there will usually be Series connection of all ammeters to indicate total generator output One ammeter indicating the output of all generators One ammeter per generator indicating the output of each individual generator.
A generator failure is usually indicated by
The ammeter reading decreasing or showing a discharge of a red warning light illuminating The electrical services failing to function The voltmeter reading increasing, the ammeter reading showing discharge and the red warning light illuminating.
If a generator fails in flight The wattmeter will show an increase The voltmeter will read zero The ammeter reading will decrease.
If one generator should fail The engine concerned should be immediately feathered The failed generator should be switched off and the electrical system be used as
normal The failed generator should be switched off, and all unnecessary electrical services selected off.
In a twin engine aircraft fitted with two generators, if one should fail
The failed generator must be isolated The failed generator must be stopped Both generator must be switched off.
Voltage is controlled in a generator by Moving the generator brushes A voltage regulator It remains uncontrolled.
A voltage regulator Regulates the amount of current supplied by the battery to operate the generator Provides a constant current flow from the generator with changes of generator speed Maintains a steady generator voltage with changes of generator speed.
In an aircraft system generator voltage is regulated by Changing the generator speed Varying the generator field strength Increasing and decreasing the load.
The resistance of carbon Increases under pressure Decreases under pressure Remains the same under pressure.
To increase the voltage setting of a carbon pile regulator Loosen the carbon pile Turn the trimmer resistance Tighten the carbon pile.
Under high voltage output the carbon pile will Remain inert Increase its resistance Decrease its resistance.
Heat dissipitation in a carbon pile regulator is aided by Fins and blast cooling Fins and ceramic casing Fins and current resistors.
A generator cut-out is provided To prevent discharge of the battery through the generator To prevent the battery form being overcharged To isolate the generator in a crash.
On a 24-volt system the generator reverse current cut-out contacts close at 26 volts 24 volts 27 volts.
Generator cut-out contact are kept open by Magnetism Spring tension Generator speed.
Reverse current cut-out contacts are closed by Magnetism Spring tension Generator speed.
Load sharing is achieved by Equalizing coil in the voltage regulator varying the current in the filed coils Equalizing coils in the cutout varying the current in the filed Equalizing coils in the voltage regulator varying the potential of the armature.
A circuit breaker is a device for Earthing the magnetos when selected off Isolating the battery when using the ground batteries Isolating the service on overload.
A trip free circuit breaker is one which Cannot be reset by holding the button in while the fault persists Must remain held in during the checks to find the fault Can be reset by holding the button in while the fault persists.
Circuit breakers are fitted In series with the load Across the load Parallel with the load.
A non trip free circuit breaker is A wire placed in a conductor which melts under overload An on-off type tumbler switch One which can be reset in flight by pushing a button.
A trip free circuit breaker that has been tripped due to overload Can be reset manually and will make a circuit if held in under fault conditions Cannot be reset and must be held in to make a circuit Will not remain set after it has manually been placed in the reset position unless
the circuit condition has returned to normal.
When selecting a fuse for a circuit the governing factor is The resistance of the circuit The power requirement of the circuit The voltage of the circuit.
Spare fuses are carried in an aircraft At the discretion of the operator For DC generators only By law with a stated minimum requirement.
Assuming a 5-amp circuit has failed during flight and investigation shows that the fuse has blown, the action to be taken is Leave the switch on and replace the failed fuse with one of a higher rating Switch off and replace the fuse with another of the correct rating for the circuit. Repeat this action as often as necessary Switch off and replace the failed fuse with one of the same rating, once only.
Battery capacity percentage efficiency must always be Above 90% Above 80 % Above 70 %.
In an AC circuit The battery is connected in series The battery is connected in parallel A battery cannot be used because it is DC.
A lead acid battery is checked for serviceability by Using an ammeter in a circuit Measuring the specific gravity of the electrolyte Using an ohmmeter.
Two 12 volts 40 amp/hour batteries connected in series will produce 12 volts 80 amp/hr 24 volt 80 amp/hr 24 volt 40 amp/hr.
A short circuit in a single pole electrical circuit would be caused By an open circuit between a an item of equipment and earth When wiring between the source of supply and an item of equipment goes down to earth By a broken conductor between the source of supply and an item of equipment.
An electrical system which uses the aircraft structure as a return path for current ,is known as A double pole circuit An earth return circuit A single phase circuit.
In a double pole circuit The current passes out through one wire, and is returned through a second wire The current passes out through one wire and is returned via the airframe The current is supplied by one wire and the current is returned through the aircraft bonding system.
In a dipole circuit if the conductors are shorted together then The fuse will blow The load will operate normally The DC generator will burn out.
Static electrical charges and currents in an aircraft structure are evened out by Screening Bonding Anodising.
Bonding is used to protect the aircraft against fire from arcing of static electricity by Maintaining a different electrical potential throughout the structure Providing an earth return Ensuring the same electrical potential of all metal components.
The purpose of electrical bonding on aircraft is To prevent compass system malfunction and accumulation of local static charges To isolate all components electrically and therefore make static potential constant To provide a low resistance path for earth return circuits and safely dissipate local static charges and lightning strikes.
Electrical components of aircraft system are screened to Bond the circuit to reduce the risk of fire Prevent short circuit in radio equipment Prevent them interfering with the function of radio equipment.
Static discharges are fitted to aircraft to Prevent the tires from bursting on loading Minimize radio interference Acts as an earth return in a single pole electrical system.
When the RPM of shunt wound DC motor increases the current drawn by it Decreases Remain the same Increases.
Static electrical charges and currents in an aircraft structure are evened out by..... Screening Bonding Anodising.
Bonding is used to protect the aircraft against fire from arcing of static electricity by....
Maintaining a different electrical potential throughout the structure Providing an earth return Ensuring the same electrical potential of all metal components.
The purpose of electrical bonding on aircraft is To prevent compass system malfunction and accumulation of local static charges To isolate all components electrically and therefore make static potential constant To provide a low resistance path for earth return circuits and safely dissipate local static charges and lightning strikes.
Electrical components of aircraft system are screened to Bond the circuit to reduce the risk of fire Prevent short circuit in radio equipment Prevent them interfering with the function of radio equipment.
Static discharges are fitted to aircraft to Prevent the tires from bursting on loading Minimize radio interference Acts as an earth return in a single pole electrical system.
When the RPM of shunt wound DC motor increases the current drawn by it Decreases Remain the same. Increases.
The direction of rotation of the armature in a DC motor can be reversed by Changing the current direction through the armature, and the direction of the magnetic filed Selecting the motor control to off, which effectively converts the back EMF Changing the direction of the magnetic field or changing the current direction through the armature.
Series wound DC motors have High resistance windings and low starting torque High resistance windings and high starting torque Low resistance windings and high starting torque.
Actuator motors are usually Compound wound Shunt wound Series wound.
An inching control is A rotary actuator A linear actuator A combination of rotary and linear actuator.
Actuator travel is controlled by Limit micro switch Mechanical stops Mechanical indicators.
Friction clutches are fitted to actuator for Protection against supply failures Protection against brake on loads Protection against mechanical overloads.
Electro mechanical brakes are fitted to actuators To prevent motor over run when power is switched off To control the speed of the actuator To prevent lead screw runaway.
Rotary actuators are used for Undercarriage retraction Movement of control surfaces Operation of fuel cocks.
Control trimming devices are operated by Rotary actuators Linear actuators Pneumatic rams.
An inverter changes Series/parallel AC into DC Direct current into alternating current Wild DC into wild AC.
The alternating current supplied to aircraft instruments is usually produced by the inclusion of An alternator mechanically driven by the engine A transformer An inverter.
A device used for changing AC to DC A rotary transformer A rectifier An alternator.
The voltage frequency required for electrical instruments is 200 volts 600 hz 200 volts 400 hz 115 volts 400 hz.
A rotary transformer is a device used for Stepping up or down AC voltages Stepping up or down DC voltages Stepping up or down both AC and DC.
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