RAD 214 Radiographic Equipment

Converts mechanical energy into electrical energy

convert electrical energy into mechanical enery

complete the alternating circuit in simple electric generator (attached to carbon "brushes")

1/60 of a second

graph representing the sine of the angle between the plane of the armature and a plane perpendicular to the magnetic field

North

• a powerful electromagnet
• an armature

2 interacting magnetic fields (one created by a current carrying wire, and an existing magnetic field)

• Effective resistance
• root mean square (rms) value

• Material
• Length
• Cross sectional area
• Temperature

• Resistance (Material, Length, area, temp.)
• Inductance reactance (Lenz's Law (back emf))
• Capacitive reactance

split-ring commutator

• 1. Can be transformed
• 2. Less power loss (through heat loss)

P (watts)= V (volts) x I (amps)

P_L = I²R

• Thumb- direction of the electron flow
• fingers- wrap in the direction of the magnetic field

• Thumb- direction of the current flow
• fingers- wrap in the direction the magnetic field

• thumb- direction of the armature movement
• index finger- direction of the magnetic field (S)
• middle finger- direction of the electron flow

• thumb- direction of the armature movement
• index finger- direction of the magnetic field (S)
• middle finger- direction of the current flow

• thumb- direction of the armature movement
• index finger- direction of the magnetic field (S)
• middle finger- direction of the current flow

• thumb- direction of the armature movement
• index finger- direction of the magnetic field (S)
• middle finger- direction of the electron flow

• DC motor
• synchronous AC
• induction AC

• AC
• DC

turns at the same speed as the armature of the AC generator supplying the current (or a multiple of the armatures speed) (used in clocks or timing devices)

• uses the stationary magnets of a stator, energized in sequence by a multiphase current, to interact through the motor principle with the copper bars (wrapped around an iron core) of a rotor
• -uses no direct contact
• -used for a rotating anode

• 3500 rpm
• -anode always spins at the same speed

• -Changes the voltage of AC with no electrical contact or moving parts (electomagnetic induction principle)
• -no appreciable loss of electrical enery (less than 5%)

• Air core
• open core
• closed core
• shell

two insulated coils laying side by side

• V_S/V_P =N_S/N_P
• Voltage (emf) in the secondary coil is to the emf in the primary coil, as the # of turns in the secondary is to the # of turns in the primary

• -iron core inserted in coils of wire
• -experiences leakage flux (loss of magnetic flux at the ends of the iron cores)

• -heavily insulated coils called 'windings' wrapped around a square or circular iron core
• -experiences transformer loss in the form of eddy currents
• -lamination hinders the formation of eddy currents
• -this is the type of transformer used for x-ray generating equipment

• -used as commercial or power transformer
• -laminated silicon steel with 2 rectangular holes
• -windings around central portion

• -copper loss (I²R)- resistance
• -eddy loss-heat generated by changing electical current (reduced by lamination w/silicon steel plates)
• -hysteresis- heat generated by constant reorientation of magnetic dipoles (coercivity -requires energy to reorient poles [causes hysteresis] (reduced by silicone steel lamination))

• -Varies input voltage to a transformer to control output voltage by selection of # of turns tapped on the secondary side
• -sets your kV
• -between source of AC and the primary side of the transformer
• -single coil serves as primary and secondary

seconday voltage/primary voltage= #tapped turns /#primary turns

• filament circuit- carries current to heat the filament
• tube circuit-carries the current that passes from cathode to anode (electrodes) to produce x-rays

• Self-rectified
• vacuum tube
• solid state

• -uses no diodes
• -no protection for the filament
• -self-half wave
• -single pulse
• -100% rippple with a pause
• -forward bias (useful half of the voltage cycle)
• -low heat loading capacity
• -limited to low exposure factors
• -100% suppression
• -single phase

• -half-wave
• -one-pulse
• -100% ripple w/ a pause
• -100% suppression
• -diode protects tube filament
• -single phase

• -single phase
• -half-wave
• -one- pulse
• -100% ripple w/pause
• -100% suppression
• -increased load capacity
• -increased effeciency
• -increased filament protection

• -full-wave
• -2 pulse
• -single phase
• -100% ripple
• -100% inversion
• -high % of low energy x-rays produced

from n to p

from p to n

Converts AC to useable DC

• -conduction
• -forbidden
• -valence

silicon; 4 e^-

• -5 valence e^-
• -added to Si
• -creates donor or n-type atom
• -makes Si a conductor

• -3 valence e^-
• -added to Si
• -creates acceptor or p-type atom
• -makes Si an insulator

the potential difference that exists between a n-type ion and a p-type ion in a diode

• -more complex
• -2 p-type and 2 n-type layer (makes 3 n-p junctions)
• -can hold or release large amounts of current

• -compact size
• -no filament (means no filament transformer)
• -low forward voltage drop
• -low reverse current
• -long life

-primary side

• -thin strip of metal prevents overload
• -primary side

• -changes voltage to set kV
• -primary side

• -Primary side
• -metering device that indicates the desired kVp

• -primary side
• -controls the current to the primary coil serving to complete the x-ray exposure

• -primary side
• -completes the circuit
• -protects the person making the exposure from electical shock

• -primary side
• -built into the exposure switch
• -5 types (mechanical, synchronous, electronic, mAs, and AEC)

• -Primary
• -operates by clockwork
• -exposure time must be greater than 1/4 of a second

• -Primary
• -powered by synchronous motor
• -minimum exposure time is 1/60 sec.
• -timer counts by waveform

• -primary
• -we use
• -most sophisticated
• -operate on variable resistance
• -can be use for rapid serial exposure
• -exposure time as small as 1 ms

• -secondary (b/c it monitors actual tube current)
• -factors time and mA to shut off at correct mAs
• -not really a timer

• -primary
• -measure quantity of radiation reaching the IR to provide the required optical density

• -primary
• -terminates the exposure in the event of AEC failure
• -minimum exposure response time is 1 ms

• -Primary
• -additional protection from overloading

• -primary
• -supplies the heating current for the filament
• -rheostat (variable resistor) reduces current to 3-5 amp and 6-12 Volts

• -primary
• -connected in series with the filament circuit to measure current (for proper heat production w/corresponding mA)
• -space charge compensator automatically corrects to maitain constant mA over wide range of kV

• -primary
• -primary winding of the transformer

• -primary
• -

• -secondary
• -smaller wires that primary b/c of smaller amps

• -secondary
• -connected in series with the high voltage/low amp secondary circuit of the transformer

• -secondary
• -changes AC to DC
• -increases heating capacity permitting larger exposures

• -secondary
• -hazard reduced by insulation, grounding, and grounding of the secondary winding of the step-up transformer at its mid-point

-secondary

• -secondary
• -considered part of the x-ray tube
• -contains stator induction motor

• -6 pulse-13% ripple
• -12 pulse- 5% ripple
• -Coils are wound in delta or star pattern
• -primary is always delta
• -secondary can be delta or star
• -rated up to 1000 mA (kV max. 80)
• -exposure time down to 1 ms
• -nearly constant potential (small ripple)

• -1% ripple
• -uses high-frequency circuit
• -60 Hz converted to 500-25,000 Hz
• -inverter circuits convert DC to square pulses
• -Uses an inverter module