SET 2 ECT Flashcards
What is the basic unit of capacitance?
The farad
What type of electrical component stores energy in a magnetic field?
Inductor
Suppose the resistance is 472 Ω, and the current is 875 mA. Thesource voltage must therefore be
413 V
What formula is used to calculate voltage in a circuit?
Voltage (E) equals current (I) multiplied by resistance (R)
Which of the following measurements are commonly made using a multimeter?
Voltage and resistance
How is an ammeter usually connected to a circuit?
In series with the circuit
A source delivers 12 V and the current is 777 mA. The bestexpression for the resistance is
15.4 Ω
What does the abbreviation “LED” stand for?
Light Emitting Diode
What formula is used to calculate resistance in a circuit?
Resistance (R) equals voltage (E) divided by current (I)
What is the ability to store energy in an electric field called?
Capacitance
Which of the following electronic components can amplify signals?
Transistor
What type of electrical component consists of two or more conductive surfaces separated by an insulator?
Capacitor
What is the voltage across a 2-ohmresistor if a current of 0.5 amperes flows through it?
1 volt
What is the name for standardized representations of components in an electrical wiring diagram?
Schematic symbols
Which semiconductor component has a gate electrode?
Field effect transistor
What is the voltage across a 10-ohmresistor if a current of 1 ampere flows through it?
10 volts
What is the basic unit of inductance?
The henry
What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms?
1.5 amperes
What electronic component allows current to flow in only one direction?
Diode
What is probably happening when an ohmmeter, connected across a circuit, initially indicates a low resistance and then shows increasing resistance with time?
The circuit contains a large capacitor
Which instrument would you use to measure electric potential or electromotive force?
A voltmeter
Which of the following might damage a multimeter?
Attempting to measure voltage when using the resistance setting
What are the names of the two electrodes of a diode?
Anode and cathode
What is the resistance in a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
8 ohms
What electrical parameter is controlled by a potentiometer?
Resistance
Suppose the resistance is 473,332 Ω, and the current flowingthrough it is 4.4 mA. The best expression for the voltage of thesource is
2.1 kV
Suppose you double the voltage in a simple dc circuit, and cutthe resistance in half. The current will
Become four times as great.
Suppose the dc voltage is 550 mV and the current is 7.2 mA.Then the resistance is
76 Ω
Which of these components is made of three layers of semiconductor material?
Bipolar junction transistor
Which semiconductor component has an emitter electrode?
Bipolar transistor
What instrument is used to measure resistance?
An ohmmeter
What electrical component is used to protect other circuit components from current overloads?
Fuse
What is the resistance of a circuit in which a current of 3 amperesflows through a resistor connected to 90 volts?
30 ohms
What class of electronic components is capable of using a voltage or current signal to control current flow?
Transistors
An atom’s atomic number is determined by the number of
Protons
What does the abbreviation “FET” stand for?
Field Effect Transistor
What is the term that describes a transistor’s ability to amplify a signal?
Gain
Given a dc voltage source delivering 24 V and a resistance of 3.3kΩ, what is the current?
7.3 mA
Given a dc voltage source of 3.5 kV and a resistance of 220 Ω,what is the current?
15.91A
Which instrument is used to measure electric current?
An ammeter
What is the ability to store energy in a magnetic field called?
Inductance
What type of component is often used as an adjustable volume control?
Potentiometer
What is the correct way to connect a voltmeter to a circuit?
In parallel with the circuit
What is the resistance of a circuit that draws 4 amperes from a 12- volt source?
3 ohms
What electrical component is used to connect or disconnect electrical circuits?
Switch
What electrical component stores energy in an electric field?
Capacitor
What is the current flowing through a 24-ohmresistor connected across 240 volts?
10 amperes
What electrical component is usually composed of a coil of wire?
Inductor
Which of these components can be used as an electronic switch or amplifier?
Transistor
You can expect to find a wiring diagram
In the service/repair manual for a two-way radio.
What electrical component is used to oppose the flow of current in a DC circuit?
Resistor
What is the current flowing through a 100-ohmresistor connected across 200 volts?
2 amperes
What is the voltage across a 10-ohmresistor if a current of 2 amperes flows through it?
20 volts
How is a semiconductor diode’s cathode lead usually identified?
With a stripe
Which of the following precautions should be taken when measuring circuit resistance with an ohmmeter?
Ensure that the circuit is not powered