MRA Electrical Module 4/6

meow

What opposes a change in current flow?

Induction

What is induction measured in?

Henrys

What is inductive reactance measured in?

Ohms

What does an inductor do in a DC current?

Opposes change in current

What is this symbol?

Inductor

What is this symbol?

Capacitor

In a power supply that converts AC to DC, what is used to filter the pulsing output?

Capacitor

What will a capacitor do a DC circuit once it is fully charged?

It will act as an open

This kind of capacitor can only be used in one kind of circuit. Is it AC or DC?

DC

When testing a capacitor, if the meter falls to a low resistance and then quickly climbs to overload, is the capacitor good or bad?

Good

When testing a capacitor, if the meter stays at a consistent low resistance, is it good or bad?

Bad

What electrical device can be used in a light fixture to provide a high starting voltage to the bulb?

Inductor

When does inductance occur?

Only when current is changing

When does a capacitor stop charging?

Once the charged voltage is equal to the source

When frequency increases, does inductive reactance increase or decrease?

Increase

Does inductive reactance happen in AC or DC circuits?

AC

What is capacitance also called?

Electrostatic charge

What are the 3 types of capacitors?

Polarized, variable, electrolytic

What device converts AC electricity from one level to another?

A transformer

The 3 parts of a transformer are:

Primary coil, secondary coil, core

What is the formula for turns ratio?

Primary coil loops / secondary coil loops

What type of transformer has the windings isolated from each other?

Isolation Transformers

What transformer uses only 1 coil and uses a tap connection?

Autotransformer

What transformer uses 2 primary and 1 secondary coil?

Control Transformer

What is used on the secondary coil of a transformer to get different voltages?

Tap Connection

What 3 things do you need to consider when sizing a transformer?

Available input voltage, Desired output voltage, Output current

When should you consider inrush current?

If you are working with a motor

Do transformers change AC voltage to DC voltage?

No

Can a transformer be used with DC voltage?

No

What is the formula for output voltage?

Voltage primary / turns ratio

If you read resistance across the primary and secondary on a transformer, what reading should you get?

OL

Can transformers also step up voltage?

Yes

If you step up voltage using a transformer, what happens to the current?

It is stepped down

In a transformer, the power in the primary is _____ the power in the secondary.

Equal to