Primary ciruit Flashcards
(30 cards)
measures the voltage provided to the x-ray imaging system and adjust that voltage precisely 220 V.
Line Voltage Compensator
Older models require manual adjustment of the voltage and therefore incorporates a ___
line voltage meter
adjusts the voltage supplied to specific circuit of the x-ray machine
Autotransformer
allow the radiologic technologist to select the voltage and therefore control the amount of voltage that will eventually flow across the x-ray tube.
kVp selector
kVp selectors can be a ___ or ___ kVp selector
major or minor
Major kVp selector - ?
increment of 10 kVp
Minor kVp selector -?
increment of 1 kVp
placed across the output terminals of the auto transformer and therefore actually reads voltage in the primary circuit and not the kVp
kVp meter
reads voltage in the primary circuit and not the kVp
kVp meter
the kVp meter is also known as
pre-reading kVp meter
it registers kVp because of known multiplication factors of the turns ratio of the step-up transformer.
kVp meter
consists of electronic device whose action is to make or break the high voltage across the tube
Timer Circuit
? - starts the exposure by pressing the exposure button
? - stops the exposure at predetermined time
radiologic technologist;
timer
automatically terminate the exposure after a prescribed time, usually approximately _ seconds
guard timer; 6 seconds
4 types of timing circuits
synchronous timer
electronic timer
mAs timer
Automatic exposure control (AEC)
make use of synchronous motor.
synchronous timer
is a device designed to drive a shaft at precisely 60 revolutions per second (rps) based on the frequency (Hz) of the supplied current.
synchronous motor
minimum exposure time is set at 1/60 seconds and timing intervals increases by multiples thereof, 1/30, 1/20, etc.
synchronous timer
needs to be reset after each exposure, and therefore cannot be used for multiple exposures
synchronous timer
- uses a rather complex circuitry
- most accurate of x-ray exposure timers
electronic timer
-allows a wide range of diamonds to be selected to a small as 1 ms.
- suitable for rapid serial exposures such as required in interventional radiology procedures
electronic timer
monitors the product of mA and exposure time and terminates exposure when desired mAs value is attained
mAs timer
designed to provide the highest safe tube current for the shortest exposure time.
mAs timer
the timer is located on the secondary circuit as it must monitor the actual tube current
mAs timer
