Review sheet Flashcards
The mirror strip on the face of some meters is there for what purpose?
more accurate reading, if you see reflection then you’re reading at the wrong angle
The percent error of a meter is?
constant only for full scale deflection
A meter has an accuracy of 3% at full scale deflection. It reads 120v on the 250v scale. What is the correct reading?
- 5volts to 127.5volts
250x0. 03= 7.5 then add/subtract to voltage reading
comparing a meters reading with a precisely accurate laboratory meter is called?
calibrating
how does the digital meter differ from the analog?
digital is a number
analog is a pointer
what are the two common type of portable digital meters?
handheld and bench type
The window where the reading of the digital meter appears is called the?
display
What is the significance of a bar graph display on a digital meter?
gives analog indication of full scale reading
What is meant by the resolution of a digital meter?
least significant figure of the digital display
where is the zero adjust screw located on a meter?
the front
function of the zero ohms adjustment knob?
compensate for voltage variations in battery
True or False? Digital meters have d’arsonval meter movement?
false
True or False? Reversing the polarity of the leads will damage a digital meter
False
True or False? digital meters require a separate battery for the read out?
true
If the range selector switch is set to the lowest voltage range, the multiplier resistance will be at its ________ value?
lowest
A voltmeter has a range selector switch marked 10v, 50v, 150v. Coil draws 50microamps on fsd. What is the sensitivity?
same for all ranges
What indication will result with a break in the test leads of any voltage tester?
no voltage 0v
What category of voltages is the solenoid-and-plunger tester ideal for?
nominal voltages
How is a shunt connected in relation to the coil of the galvanometer?
in parallel
Why is it necessary to use a make-before-break type of switch for the range switch of an ammeter?
to prevent excessive current flow
What is the effect on the ammeter reading if the leads are changed to a smaller conductor size?
meter reads lower current than circuit current
What is the function of the resistor in the ohmmeter?
to compensate for drop in the battery output voltage
Which of the 3 coils in the wattmeter is the moveable coil?
potential coil (voltage coil)
If the polarity of a wattmeter is incorrect what happens?
pointer tries to move backwards
What keeps the pointer at 0 when the meter is not registering any power?
spiral spring
What is the purpose of damping magnets in the energy meter?
to create counter torque on the disk allowing for speed adjustment
