E6F Electro-optical technology: photoconductivity; photovoltaic devices; optical sensors and encoders; optically isolated switching

- [[E6F01]] (C)
What absorbs the energy from light falling on a photovoltaic cell? #card
	- [[A.]] Protons
	- [[B.]] Photons
	- [[C.]] Electrons
	- [[D.]] Holes
- [[E6F02]] (A)
What happens to photoconductive material when light shines on it? #card
	- [[A.]] Resistance decreases
	- [[B.]] Resistance increases
	- [[C.]] Reflectivity increases
	- [[D.]] Reflectivity decreases
- [[E6F03]] (D)
What is the most common configuration of an optoisolator or optocoupler? #card
	- [[A.]] A lens and a photomultiplier
	- [[B.]] A frequency-modulated helium-neon laser
	- [[C.]] An amplitude-modulated helium-neon laser
	- [[D.]] An LED and a phototransistor
- [[E6F04]] (B)
What is the photovoltaic effect? #card
	- [[A.]] The conversion of voltage to current when exposed to light
	- [[B.]] The conversion of light to electrical energy
	- [[C.]] The effect that causes a photodiode to emit light when a voltage is applied
	- [[D.]] The effect that causes a phototransistor’s beta to decrease when exposed to light
- [[E6F05]] (A)
Which of the following describes an optical shaft encoder? #card
	- [[A.]] A device that detects rotation by interrupting a light source with a patterned wheel
	- [[B.]] A device that measures the strength of a beam of light using analog-to-digital conversion
	- [[C.]] An optical computing device in which light is coupled between devices by fiber optics
	- [[D.]] A device for generating RTTY signals by means of a rotating light source
- [[E6F06]] (C)
Which of these materials is most commonly used to create photoconductive devices? #card
	- [[A.]] Polyphenol acetate
	- [[B.]] Argon
	- [[C.]] Crystalline semiconductor
	- [[D.]] All these choices are correct
- [[E6F07]] (B)
What is a solid-state relay? #card
	- [[A.]] A relay that uses transistors to drive the relay coil
	- [[B.]] A device that uses semiconductors to implement the functions of an electromechanical relay
	- [[C.]] A mechanical relay that latches in the on or off state each time it is pulsed
	- [[D.]] A semiconductor switch that uses a monostable multivibrator circuit
- [[E6F08]] (C)
Why are optoisolators often used in conjunction with solid-state circuits that control 120 VAC circuits? #card
	- [[A.]] Optoisolators provide a low-impedance link between a control circuit and a power circuit
	- [[B.]] Optoisolators provide impedance matching between the control circuit and power circuit
	- [[C.]] Optoisolators provide an electrical isolation between a control circuit and the circuit being switched
	- [[D.]] Optoisolators eliminate the effects of reflected light in the control circuit
- [[E6F09]] (D)
What is the efficiency of a photovoltaic cell? #card
	- [[A.]] The output RF power divided by the input DC power
	- [[B.]] The output in lumens divided by the input power in watts
	- [[C.]] The open-circuit voltage divided by the short-circuit current under full illumination
	- [[D.]] The relative fraction of light that is converted to current
- [[E6F10]] (B)
What is the most common material used in power-generating photovoltaic cells? #card
	- [[A.]] Selenium
	- [[B.]] Silicon
	- [[C.]] Cadmium sulfide
	- [[D.]] Indium arsenide
- [[E6F11]] (A)
What is the approximate open-circuit voltage produced by a fully illuminated silicon photovoltaic cell? #card
	- [[A.]] 0.5 volts
	- [[B.]] 0.7 volts
	- [[C.]] 1.1 volts
	- [[D.]] 1.5 volts