RST Study - General

Question 1

If a circuit has constant voltage and resistance goes down, what happens to the power dissipated?

Answer 1

Increases (P=E 2 /R)

Question 2

If 120v is applied to a 60 watt light bulb, what is the current?

Answer 2

.5amps

Question 3

What is a microsecond?

Answer 3

.000001 second

Question 4

Two 100 ohm resistors in parallel equal what?

Answer 4

50 ohms

Question 5

In a purely capacitive circuit, current and voltage are what?

Answer 5

90 degrees out of phase

Question 6

In series circuit, there are how may paths for current to follow?

Answer 6

One

Question 7

An SCR is being replace by what in a new AC motors?

Answer 7

IGBT (Insulated Gate Bipolar Transistor)

Question 8

In PLCs, a solenoid is an __?

Answer 8

Output

Question 9

With a constant voltage, what happens to the power dissipated in a circuit if the resistance decreases?

Answer 9

Power Increases

Question 10

The current in a series circuit ____ after passing through each resistor in the circuit.

Answer 10

Is Unchanged

Question 11

The voltage across each component of a series circuit will vary in proportion to the ___ of that circuit
component.

Answer 11

Resistance

Question 12

To change the speed of a motor utilizing a variable speed AC drive, you vary the ___.

Answer 12

Frequency

Question 13

Convert the binary number 10111 to its decimal form.

Answer 13

23

Question 14

The primary voltage of a transformer is 480v and the secondary is 2400v. The turns ratio of this transformer is?

Answer 14

1:5

Question 15

A faulty resistor has been replaced with two parallel 120 Ohm resistors. What was the value of the original
resistor?

Answer 15

60 Ohms

Question 16

When the frequency of an RL circuit increases, how is reactance affected?

Answer 16

Reactance increases. (XL = 2πfL) (Inductive reactance and frequency are directly proportional)

Question 17

What are the Two types of starting circuits in a motor?

Answer 17

Direct or Inline Starter

Question 18

How do you hook up four 8-ohm speakers up on a 8-ohm line?

Answer 18

Put two in series, paralleled with the other pair in series.

Question 19

How do voltage and current interact in an inductive circuit?

Answer 19

Voltage leads current in an inductive circuit, by as much as 90 degrees.
(Think “ELI”)

Question 20

How do voltage and current interact in an capacitive circuit?

Answer 20

Current leads voltage in a capacitive circuit, by up to 90 degrees.
(Think “ICE”)