Transducers, Instrumentation And Welding Flashcards
To just memorize shit
A device that converts one energy or physical property to another form of energy
Transducer
Transducers that do not require external power, and produces analog voltage or current when stimulated by some physical form of energy
Self Generation Type
Transducers that require an external power
Passive Transducers
A transducer consisting of a bond between two different metals wherein when the bond is heated, a direct current voltage appears across it
Thermocouple
A potential difference between the two ends of a conductor that depends on the temperature difference of the ends and the material property
Seebeck Voltage
Magnitude of Thermal Voltage (Formula)
V = c1(T2-T1) + c2(T2^2 - T1^2) wherein c1 and 2 - consts of thermocouple materials
Temperature sensors that make use of the predictable change in electrical resistance of some materials with changing temperature.
Resistance temperature detector (RTD)
RTD Linear approximations
Rt = R(1 + a(T2-T1))
A device similar to RTD except having negative temperature coefficient, less expensive but less sensitive
Thermistor (Semiconductor Resistance Sensor)
A variable resistance device that can be used to measure angular position
Potentiometer
Sensors that use the electrical property of Capacitance to make measurements
Capacitive Transducers
Sensor that use the electrical property of inductance to make measurements
Inductive Transducers (ie Ammeter)
A transducer that consists of a primary winding and two secondary windings, wound over a hollow tube. When the tube is moved in one direction from the center, the voltage induced in one winding is increased and the others decreased.
Linear Variable Differential Transformer (LVDT) #LoveWins
A passive device that converts mechanical stress into resistance
Strain Gauge
Transducers that rely on the photo electric effects.
Optical Transducers
Semiconductor light detectors that generate current or voltage when the PN junction is illuminated by light
Photodiodes
Feature of Photodiode
Excellent Linearity, Low Noise, Wide spectral respones, mechanically rugged, lightweight, long life
Ratio of output photocurrent to incident optical power
Responsivity (A/W)
The output current of a photodiode in the absence of light
Dark Current (also called as Manacop Current or Michael Current)
Minimum input optical power to generate photocurrent, equal to the rms noise current in a 1 Hz Bandwidth
Noise equivalent power
Vacuum tube devices that are extremely sensitive detectors of light in the ultraviolet, visible, and near infrared ranges. It multiplies current produced by incident light as much as 100 million times
Photomultipliers
A material which exhibits Scintillation, the property of Luminescence when excited by ionization event
Scintillator
Simple resistors made of a high resistance semiconductor that alters resistance depending on the amount of light placed over them
Photoresistor
A class of phtodetectors which can generate voltage that is proportional to the incident electromagnetic radiation intensity. It simply converts electromagnetic energy to electrical energy.
Photovoltaic Detectors
Voltage generated in Photovoltaic Cell
Vout = (Calibration Voltage)x(Intensity)
The use of the measuring devices to determine the values of varying quantities.
Instrumentation
A device used to present value of a quantity under observation
Instrument
Three General Types of Instrument
Indicating, Recording, Controlling
The process of comparing an unknown quantity with an accepted standard quantity
Measurement
The deviation of a reading or set of readings from the expected value of the measured variable
Error
Generally the fault of the person using the instruments
Gross Errors (Ewwww di marunong)
Errors caused by problems with the instrument, environmental effects, or observation errors (parallax and estimatuon)
Systematic Error
The accumulation of a large number of small effects which are neither classified as gross nor systematic
Random Errors
The difference between expected and measured value
Absolute Error
Ratio Absolute Error and Expected Value
Percentage Error
The degree of exactness compared to the expected value
Accuracy
A quantitative or numerical indication of the closeness with which a repeated set of measurements agrees with the average of the set of measurements
Precision
An instrument that operates upon the interaction of the magnetic fields between a permanent magnet and an electromagnet. The amount of movement is determined by the size of the current.
Permanent Magnet Moving Coil (PMMC)
It is attached to the pointer tail to provide mechanical balance and eliminate gravitational effect
Counterweight
Used to control the force exerted on the coil when current passes through it
Spiral Spring
It is pivoted so as to move freely when current is introduced to the system
Moving Coil
used to fix the position of the permanent magnet
Pole Shoes
Used to adjust the pointer to its initial position when no current is flowing
Zero adjustable control
it provides visual indication of the amount of current flow
Pointer
Provided by the moving coil pivoted so as to move freely when current flows to the system
Deflecting Torque/Force
Provided by the spiral spring so that the pointer will deflect back to its initial position when no current flows
Controlling Torque/Force
Provided by the coil pointer to eliminate pointer oscillation
Damping Torque/Force
An instrument used to measure the intensity of electric current flow
DC Ammeter
Properties of Ideal Ammeter
Zero internal resistance, needle deflection directly proportional to current
Properties of Real Ammeter
Small internal resistance, needle deflection not exactly directly proportional to current
It arises from the fact that the meter face may not be accurately marked
Calibration Error
The real ammeter resistance will add the resistance to the branch that will reduce current in any actual circuit
Insertion Error
An instrument used to measure voltage across two points in a circuit
DC Voltmeter
The real voltmeter resistance will reduce the resistance across the branch that will reduce voltage drop
Loading Error
An instrument used to measure the resistance across two points in a circuit
Ohmmeter
It consists of a rectifier and DC voltmeter to measure AC voltage
AC voltmeter
Generally refers to a circuit in which a load is connected between two levels of potential
DC Bridge circuit
Used to determine unknown resistance, It is balanced when reading across galvanometer is zero.
Wheatstone Bridge
A bridge that is balanced by moving the key alone the wire until the galvanometer reads zero.
Slide wire bridge
Modified version of Wheatstone Bridge elimination the effects of contact and lead resistance when measurinf low resistances from 1u ohm to 1 ohm
Kelvin Bridge
Application of Wheatstone Bridge to find the distance of a ground fault in transmission line cables
Varley Loop
Simplified version of Varley Loop used for very low resistance
Murray Loop and Slide Wire Murray Loop
Measures an unknown in terms of known calacitance in parallel with a resistor
Maxwell Bridge
Measures an unknown in terms of known calacitance in series with a resistor
Hay Bridge
Used extensively for Measurement of capacitance and the quality factor of capacitor in terms of dissipation factor
Schering Bridge
The ratio of Reactance to resistance
Dissipation Factor of Capacitor
Measures the fresquency of the voltage source using series RC in one arm and parallel RC in the adjoining arm
Wein Bridge
It is the process that joins materials, usually metals or thermoplastics, by using coalescense.
Welding
It is a combination of heat, pressure and time. It is the resistance of the material to be welded to current flow that causes a localized heating in the part.
Resistance Welding
The time between pressure application and weld
Squeeze time
Weld time in cycles
Heat or Weld time
Time that pressure is maintained after the weld is made
Hold time
Electroedes separated to permit moving of material for next spot
Off time
It is a semi automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun.
Gas metal arc welding (GMAW) , Metal Inert Gas ( MIG) , Metal Active Gas (MAG)
It is a process that produces an electric arc remained between a tungsten electron and the part to be welded.
Gas tungsten arc welding (GTAW), Tungsten inert gas (TIG)
Advantages of GTAW
Concentrated arc, No slag, no sparks and splatter, little smoke, welds more metals and alloys than any other process, good for welding thin material.
Disadvantages of GTAW
Slower travle speed, lower filler metal deposition rates, brighter UV, equipment cost
It is an arc welding process that welds metals produced by heat from an electric arc that is maintained between the tip of a consumable covered electrode and the surface of the base metal in the joint to be welded
Shielded metal arc welding (SMAW)
Advantages of SMAW
Appropriate for commonly used metals, simple tools needed, well protected
Disadvantages of SMAW
Lower consumable efficiency, difficult to weld thin materials, frequent restarts, lower operating power
Operates in which two parts to be assembled are rubbed together at lower frequency (100-300 Hz)
Friction Welding
A type of Resistance welding that combines dissimilar metals together. It creates a high temperature arc that is formed from a short quick electrical discharge
Percussion Welding (PEW) pew pew pew
A solid phase welding technique involving a stud, small pipe fitting being rotated at high speed while being forced against a substrate, generating heat by friction.
Friction Stud Welding
Welding technique that requires one part to be transmissive to a laser beam and either the other part absorptive or a coating at the interface to be absorptive to the beam.
Laser Welding
A welding technique which produces coalescence of metals by applying heat with an arc between a nonconsumable carbob (graphite) electrode and the workpiece
Carbon Arc Welding (CAW)
Is a derivation of GMAW. uses a metal tube filled with powdered flux materiala
Flux colored arc welding (FCAW)
It is an arc welding process which is the same as GTAW. The main difference is that this process positions the electrode with the body of the torch, the plasma arc can be separated from the shielding gas envelope.
Plasma Arc Welding (PAW)
A form of spot welding where a specially formed nut or bolt is welded against another mrtsl part.
Stud Arc Welding
Is a welding process that is highly useful for thick (25mm to 300mm) materials
Electroslag Welding
Welding which uses an arc between two metal tungsten electrodes in a shielding atmostphere of hydrogen.
Atomic Hydrogen Welding (AHW)
Process that requires a constantly fed consumable solid or tubular electrode. the molten weld and the arc zone are protected from atmospheric contagion by being submerged under a blanket of granular flux.
Submerged Arc Welding (SAW)
A solid state welding process that requires high temperature to join two pieces of metal then hammering them together
Forge Welding
A process that uses fuel gases and oxygen to weld. two metals are heated to a temperature that produces a shared pool of molten metal.
Oxy Fuel Welding
A special type of welding in which two pieces of materials are forged together at higher temperature and no extra weld materials is added to the weld
Upset Welding
Commonly used for plastica, and especially joining dissimilar metals. High frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure.
Ultrasonic Welding
A continuous vertical position arc welding process in which an arc is struck between the workpiece and consumable electrode
Electrogas Welding
It is a solid state welding process in which joining takes place without fusion at the interface of the parts to be welded. uses insulation displacement connectors)
Cold welding
A solid state welding technique wherein two metals are pressed together at temperatures 50-70% of the melting point
Diffusion Welding (DFW)
It is when different metals fuse together
Coalescence
The GTAW process can produce heat upto what temperature
19,500 Celsius
