105 rectifiers and transformers flashcards

A single semiconductor component that allows current to flow in one direction

Solid state diode

Diode rectifiers uses a special class of materials called

Semiconductors

An apparatus located in a circuit that acts as an insulator of electricity in one direction but conducts electricity in the opposite direction is called

Rectifier

A wave form with large gaps between positive voltage peaks is a result of which of the following?

Half-wave rectification

What type of rectification occurs when then negative voltage peak is inverted to positive voltage?

Full-wave rectification

A 3-phase, 6 pulse unit has an effective kV of about … of the peak Kip

87%

Principal disadvantage of self-rectification

Low heat loading capacity

The negative half cycle where cathode is positive and applies voltage to block current

Inverse voltage or reverse bias

A circuit that uses 1 or more solid state diodes to convert AC to DC

Solid-state diode rectifiers

Simple type uses only one-half of the useful voltage or forward bias used in Mobile radiography units

Self-rectification (half-wave)

Spinning top test can be used to determine the accuracy of which of the following?

Rectification circuit

An older component used to prevent a reverse current

Valve tube

Which material would make the best transformer core

Soft iron

The positive half cycle where electrons pass from cathode to anode and anode being positive voltage applied to allow current flow

Useful voltage or forward bias

An … is used to test the timer in 3 phase, 12-pulse equipment

Oscilloscope

The extra election in n-type can be controlled by what?

Small electric field

What type of rectifier is used in modern x-ray equipment?

Diode

Suppresses the inverse voltage

Solid state diode rectification (full rectification)

3 phase current consist of 3 single phase voltage waveforms separated by

120 degrees

A 3 phase 12 pulse unit has an effective kV of about … of the peak kVp

95%

3phase 6 pulse voltage ripple

13%

3 phase 12 pulse voltage ripple

4%

What semiconductor is most common used by manufacturers

Silicon

High frequency voltage ripple

1%

A rectifier:

Converts AC to DC

When arsenic is added to silicon it has an extra electron called

N-type

Full-wave rectified and self-rectified voltage ripple

100%

AC is best described as a current that alternates between

Positive and negative polarity

A material that has intermediate conductivity

Semiconductors

To generate 3phase 6 pulse power at least how many rectifiers are necessary

6

Is n-type silicon negative or positive?

Negative

The simplest device for testing the competence of rectifiers with single=phase equipment is the?

Spinning top

Arsenic has how many electrons in its outer orbit

5

Is p-type negative or positive

Positive

What type of transformer core is most widely used in radiographic equipment?

Closed core

When gallium is added to silicon there’s a shortage of 1 electron called

P-type

Silicon atom has 4 … atoms in its outer shell

Valence

Defined as the process of charging alternating current to (pulsating) direct current

Rectification

Which of the following principles of voltage rectification produces the maximum efficiency of x-ray production

High frequency generator

What are 3 phase generators more efficient than single-phase?

Voltage never drops to zero

A semiconductor rectifier is …

Is a solid states device

Advantage of a diode rectification ?

Increase in heat loading capacity

What is the simplest type of rectification

Self-rectification

Gallium has how many electrons in its outer shell

3

The spinning top is also usd to test the accuracy of the timer if all 4 rectifiers are known to be functioning properly in

Single-phase equipment

3 phase generator

Voltage never reaches zero

Con provide short exposure times

Small ripple 3% with 3phase, 12-pulse 13% with 3phase 6 pulse

Effective kVp 95% with 12 pulse and 87% with 6 pulse generator

3phase current

Consist of single phase current out of step with each other by 1/3 or 120 degrees

The transformer core windings are arranged in delta or star winding

If the voltage is stepped up what happens to the current in the secondary side of the transformer?

Decreases

If the voltage is stepped don what happens to the current in the secondary side of the transformer?

Increases

Which transformers has a laminated core ?

Closed core

Operates on the principle of self-induction and requires AC

Choke coil

Most advance and efficient must be heavily insulated

Shell type

How can hysteresis losses be reduced in a transformer?

Lamination

Is a variable resistor that is designed to regulate filament current

Rheostat

Is a device that varies input voltage to a transformer to control its output voltage

Autotransformer

More efficient than the air core transformer it has an iron core inserted into the coil of wire

Open core

What is the reason for using alternating current

Transformers cannot work without it

What is it called when a current is induced in a secondary coil by simply changing the current in the primary?

Mutual induction

Power loss occurs as a result of the changing magnetic fields by the AC in the windings. It’s reduced by the laminated silicon steel core

Hysteresis loss

More efficient than the previous 2 the closed core provides a continuous path for magnetic flux

Closed core

The autotransformer serves indelicately as the …

KV selector

Pertain to the loss of electrical power due to the resistance of the coils

Copper loss (I²R)

Which side is the amperage side

Filament side

Consist simply of 2 insulated coils lying side by side

Air core

What type of transformer has more coils in the secondary than in the primary?

Step-up

An electromagnetic device that changes an AC from low voltage to high voltage of high voltage to low voltage without loss of an appreciable amount of energy

Transformer

When there’s less turns in the first volt and more turns in the second volt?

Step up

When the radiographer selects kilovoltage on the control panel which device is adjusted

Autotransformer

When there’s more turns in the 1st volt and less in the 2nd volt it’s a

Step down

Swirling currents in the core itself by electromagnetic induction is minimized by use of laminated silicon steel plates highly insulated from each other by special coating

Eddy current loss or swirling currents

Autotransformer work on the principe of ?

Self-induction

Transformers only work with ?

AC current

The emf in the secondary coil is to the emf in the primary coil as the number of turns in the secondary coil is to the number of turns in the primary coil

Transformer law

2 options to control filament

Choke coil or rheostat

Transformers work on the principle of …

Electromagnetic induction