Ch.4 X-Ray Circuit Parts

autotransformer

The radiographer controls the _____ through the kVp selector of the operating console, which creates a voltage through self-induction that, when passed through the step-up transformer, becomes the kilovoltage applied to the x-ray tube to produce x-rays.

automatic exposure control (AEC)

terminates exposure (like a timer)

automatic exposure control (AEC)

____ consists of an ionization chamber that is placed between the patient and image receptor.

-As the radiation exits the patient and passes through the chamber, ionization occurs. When sufficient ionization occurs in the chamber, a signal is sent to terminate exposure

solid-state rectifier

is a device used to convert alternating current (AC) to direct current (DC) in x-ray circuits, providing efficient and reliable rectification.

rheostat

variable resistor controlled by the mA selector on the operating console

rheostat

adjusts milliamperage on the operating console, thus adjusting the amount of resistance in the filament circuit

(higher mA station number, the lower the resistance)

primary circuit

consists of:

-main power switch

-circuit breakers

-autotransformer

-timer circuit

-primary side of step-up transformer

secondary circuit

consists of:

-secondary side of step-up transformer

-mA meter

-rectifier bank

-x-ray tube

filament circuit

consists of:

-rheostat

-step-down transformer

-filaments

line compensator

a device usually wired to the x-ray machine to 220 volts

(found in primary circuit)

circuit breaker

protect against short circuits and electric shock by interrupting the flow of electricity when a fault is detected.

autotransformer

adjustable transformer controlled by the kilovolt peak (kVp selector) on the operating console

step-up transformer

used to increase the voltage from the autotransformer to the kilovoltage necessary for x-ray production

step-up transformer

dividing line between primary and secondary circuits

timer circuit

located in primary circuit because it is easier to control (turn on/off) a low voltage than a very high one

autotransformer

in the primary circuit, voltage is determined by the ____ and applied to the primary side of the step-up transformer

mA meter

device that measures tube current in milliamperes, helping to control the quantity of x-ray photons produced.

mA meter

monitors x-ray tube CURRENT

p-type, n-type

what is the rectifier pair?

half-wave retification

identify the retification

½ of the AC cycle flows through the x-ray tube and the other half is suppressed (blocked)

half-wave rectification

2 rectifiers

full-wave rectification

4 rectifiers - allows both halves of the AC cycle to be used, resulting in a smoother and more efficient output.

ripple

energy fluctuates from zero (on the line) to the maximum voltage (peak of wave)

three-phase retification

3.5 - 13% ripple

rectifiers

the one-way valves

-necessary to route the electricity through the x-ray tube correctly

exposure timer

-in filament circuit

-works in concert with the rheostat; together they determine the QUANTITY of ELECTRONS boiled off of the filament and available for xray

step-down transformer

used in filament circuit to INCREASE the CURRENT by REDUCING the VOLTAGE that is applied to the filament

tube current

milliampere (mA)

-reflects rate of flow of electrons passing through x-ray tube during exposure

filaments

tiny coils of wire housed in the cathode of the x-ray tube that emit electrons when heated, contributing to the generation of x-rays.

filaments

represented on the operating console by the “large focal spot” and “small focal spot”

goal of filament circuit

boil electrons out of the filament wire