NTC Class C Element 3 (III)

[Information] : Where a question shows [Information]. All the information given below that question is OK

The units of 1.Voltage : 2.Current : 3. Resistance : 4. Power are: [Information]
1. 1. Volt (V)
2. 2. Ampere (A)
3. 3. Ohm (R)
4. 4. Watt (W)
The symbols used to denote units of 1.Voltage : 2.Current : 3. Resistance : 4. Power are: [Information]
1. 1. V (E)
2. 2. I (A)
3. 3. Ω (Ohms)
4. 4. W
The units of 1.Inductance : 2.Capacitance : 3. Frequency : 4. Reactance are: [Information]
1. 1. Henry
2. 2. Farad
3. 3. Hertz
4. 4. Ohms (Ω)
The symbols used to denote 1.Inductance : 2. Capacitance : 3. Frequency : 4. Reactance are: [Information]
1. 1.L
2. 2.C
3. 3. Hz
4. 4. X
In a schematic diagram the capital letters 1.V : 2. A : 3.R : 4.W represent: [Information]
1. 1. Voltage (V)
2. 2. Current (A)
3. 3. Resistance (R)
4. 4. Power (W)
In a schematic diagram the letters 1.L : 2.C : 3. f : 4. X represent: [Information]
1. 1. Inductance
2. 2. Capacitance
3. 3. Frequency
4. 4. Reactance
Audio frequency range is from_____
1. 20 Hz to 200 MHz
2. 20 Hz to 20 KHz
3. 200 Hz to 4 KHz
4. 300 Hz to 30 KHz
The opposition of a conductor to the flow of current is___
1. Inductance
2. Resistance
3. Capacitance
4. Conductance
1. A short circuit has a resistance of _____
2. Open circuit has the resistance of ____
1. 1. zero
2. 1. infinity
3. 2. zero
4. 2. infinity
Reactance : Impedance : Conductance : Admittance are : [Information]
1. Reactance is the opposition of a circuit element to a change in current or voltage, due to that element's inductance or capacitance and is mathematically symbolized by the letter “X” and is measured in the unit of ohms (Ω).
2. Impedance, denoted Z, is an expression of the opposition that an electronic component, circuit, or system offers to alternating and/or direct electric current and is measured in the unit of ohms (Ω)
3. Conductance is an expression of the ease with which electric current flows through a substance. In equations, conductance is symbolized by the uppercase letter G. The standard unit of conductance is the siemens (abbreviated S).
4. Admittance is a measure of how easily a circuit or device will allow a current to flow. It is defined as the reciprocal of impedance. The SI unit of admittance is the siemens (symbol S)
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. [Infromation]
1. Ohms Law stated in formula where I = Amps (Current) : V (E) = Volts and R = Resistance. When using Ohms Law all the units must be the same value.
2. To find the Voltage, ( V). V = I x R : V (volts) = I (amps) x R (Ω)
3. To find the Current, ( I ). I = V / R : I (amps) = V (volts) / R (Ω)
4. To find resistance. R = V / I : R (Ω) = V (volts) / I (amps)
The electrical power (P) formula : [Information]
1. P = I (squared) x R
2. P = V (squared) / R
3. P = I x V
4. A battery voltage of 18 volts and a lamp resistance of 3 Ω, Using Ohm’s Law (I = V/R) to determine current, we get: 6amps
  Now that we know the current (6A) , we can take that value and multiply it by the voltage to determine power (P = I X V) : 6 (amps) X 18 (volts) = 108 watts
The longer the copper wire ________
1. the lower the resistance
2. same resistance
3. higher resistance
4. zero resistance
What is the total voltage of a circuit having a 0.5A current flowing through a 70 ohm resistor ?
1. 0.5V
2. 75V
3. 25V
4. 35V
The speed of light is approximately ________meters per second.
1. 250,000,000 m/sec
2. 300,000,000 m/sec
3. 330,000,000 m/sec
4. 350,000,000 m/sec
What is the approximate length for a 1/2-wave dipole antenna cut for 3.550 MHz?
1. 42 feet
2. 84 feet
3. 132 feet
4. 263 feet
How many hertz are there in a kilohertz?
1. 10,000
2. 1,000
3. 100
4. 10
Decibel : [Information]
1. The decibel (symbol: dB) is a unit of measurement used to express the ratio of one value of a physical property to another on a logarithmic scale. It can be used to express a change in value (e.g., +1 dB or −1 dB) or an absolute value.
2. The decibel ( dB) is used to measure sound level, but it is also widely used in electronics, signals and communication. The dB is a logarithmic way of describing a ratio. The ratio may be power, sound pressure, voltage or intensity or several other things.
3. A decibel is a relationship between two values of power.
  Power Gain...........................Power Loss
  3 dB = 2X power.................. – 3 dB = 1/2 power
  6 dB = 4X power................ – 6 dB = 1/4 power
  10 dB = 10X power............. – 10 dB = 1/10 power
  20 dB = 100X power........... – 20 dB = 1/100 power
Photoconductivity effect:
1. Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light, ultraviolet light, infrared light, or gamma radiation
1.Direct current (DC) : [Information]
2. Alternating current (AC): [Information]
1. 1. An electric current flowing in one direction only.
2. 1. A battery is a good example of a DC power supply.
3. 2. An alternating current reverses its direction many times a second at regular intervals, typically used in power supplies.
4. 2. Alternating current is an electric current which periodically reverses direction, in contrast to direct current which flows only in one direction.
Radio Frequency:Radio frequency (RF) refers to the rate of oscillation of electromagnetic radio waves in the range of 3 kHz to 300 GHz, as well as the alternating currents carrying the radio signals. This is the frequency band that is used for communications transmission and broadcasting. [Information]
1. MF - Medium Frequency : 300–3,000 kHz
2. HF - High Frequency : 3–30 MHz
3. VHF -Very High Frequency : 30–300 MHz
4. UHF - Ultra High Frequency : 300–3,000 MHz
Effective Radiated Power (ERP) : [Information]
1. ERP. It is the output power of the transmitter, plus the gain of the antenna, minus the attenuation and losses incurred by cable runs and connectors in-between the transmitter and antenna.
2. ERP measures the combination of the power emitted by the transmitter and the ability of the antenna to direct that power in a given direction. It is equal to the input power to the antenna multiplied by the gain of the antenna.
1. Giga (G) : 2. Mega (M): 2. Kilo (k) : 4. Centi (c) : [Information]
1. 1. G = one billion(1000000000)
2. 2. M = one million (1000000)
3. 3. k = one thousand (1000)
4. 4. c = one hundredth (0.01)
1. milli (m) : 2. micro (µ) : 3. nano (n) : 4.pico (p) : [Information]
1. 1. m = one thousandth (0.001)
2. 2. µ = one millionth (0.000001)
3. 3. n = one billionth (0.000000001)
4. 4. p = one trillionth (0.000000000001)
1.Microfarad (µF) : 2. Pico farad (pF) : 3. millihenry (mh or mH) : 4. microhenry (µH) : [Information]
1. 1. µF = equivalent to 0.000001 Farad
2. 2. pF = equivalant to (0.000000000001) of Farad.
3. 3. mh or mH = equivalant to (0.001) of a Henry
4. 4. µH = equivalant to (0.000001) of a Henry
What type of circuit that has its components junctions connected at a common point ?
1. Common bridge
2. Common circuit
3. Common connection
4. Common wiring
Resonance is the condition that exists when: [Information]
1. Resonance is the condition that exists when: inductive reactance (XL) and capacitive reactance (XC) are equal
2. Parallel tuned circuits offer: very high (maximum) impedance (Z) at resonance
3. In a series resonant circuit at resonance, the circuit has low (minimum) impedance (Z)
Reactance (symbol X) and measured in unit of ohms (Ω)unit : Impedance (symbol Z) and measured in ohms [Information]
1. Reactance : In electrical and electronic systems, reactance is the opposition of a circuit element to a change in current or voltage, due to that element's inductance or capacitance. The notion of reactance is similar to electrical resistance, but it differs in several respects.
2. Reactance : There are two types of reactance: capacitive reactance (Xc) and inductive reactance (XL).
3. Impedance : Electrical impedance, measure of the total opposition that a circuit or a part of a circuit presents to electric current. Impedance includes both resistance and reactance
4. Impedance is measured in ohms and may include resistance (R), inductive reactance (XL), and capacitive reactance (XC).
The Q, or quality, factor of a resonant circuit is a measure of the “goodness” or quality of a resonant circuit. A higher value for this figure Corresponds to a more narrow bandwidth. [Information]
1. The Q measures how good a circuit is, the higher the Q the sharper the peak
2. Bandwidth : The quality factor relates the maximum or peak energy stored in the circuit (the reactance) to the energy dissipated (the resistance) during each cycle of oscillation meaning that it is a ratio of resonant frequency to bandwidth and the higher the circuit Q, the smaller the bandwidth, Q = ƒr /BW.
3. The bandwidth is determinded by the Q factor.
Resistors (R) in (1) series and in (2) parallel: [Information]
1. (1) Series : The current is the same through each resistor. The total resistance of the circuit is found by adding up the resistance values of the individual resistors: equivalent resistance of resistors in series : Rt(Resistance total) = R1 + R2 + R3 +
2. Example: Resistors 3 ohm + 4 ohm + 5 ohm connected in series. Rt = 12 ohms
3. (2) Parallel : The voltage is the same across each component of the parallel circuit. The total resistance of the circuit is found by adding up the restance values of the individual resistors:1/Rt = 1/R1 + 1/R2 + 1/R3 +
4. Example : 3 ohms (R1) + 6 ohms (R2) are connected in parallel : 1/Rt = 1/3 + 1/6 = 3/6 therefore Rt = 6/3 = 2 ohms..or..Rt = R1 x R2 / R1 + R2...3 x 6 / 3+ 6 = 2 Ohms
Capacitors (C) in (1) series and in (2) parallel: [Information]
1. (1) Series : The total capacitance is less than any one of the series capacitors’ individual capacitances. Ct (Capacitance total) 1/C = 1/C1 + 1/C2 + 1/C3 +
2. Example : Capacitors 2 F + 6 F + 8 F are connected in parallel. Total capacitance (Ct) is 1/Ct = 1/2 + 1/6 + 1/8 = 19/24 therefore Ct (24/19) = 1.26 F
3. (2) Parallel : the total capacitance is more than any one of the individual capacitors’capacitances Ct = C1 + C2 + C3 +
4. Example : 5 µF + 7 µF + 8 µF are connected in series. Ct = 20 µF
Inductors (L) in (1) series and in (2) parallel: [Information]
1. (1) Series : Inductors in series have a Common Current flowing through them.The total inductance (Lt) = L1 + L2 + L3 +
2. Example : Inductances 500 uH + 100 uH + 600 uH + 200 uH are connected in series. Lt = 1400 uH
3. (2) Parallel : Inductors in Parallel have a Common Voltage across them. Total inductance (Lt) 1/Lt = 1/L1 + 1/L2 + 1/L3 +
4. Example : Inductances 14 H + 3 H + 7 H are connected in parallel. Total inductance (Lt). 1/Lt = 1/14 + 1/3 + 1/7 = 23/42 therefore Lt (42/23) = 1.82 H
55 microfarad capacitor be also written ?
1. 55F
2. 55nF
3. 55uF
4. 55pF
168 megohm value resistor can also be written as ____
1. 168 MW
2. 168 k
3. 168 MΩ
4. 168 mW
1.2 gigahertz frequency also be written ?
1. 1.2 GHz
2. 1.026MHz
3. 1.131MHZ
4. 1.456MHZ
Determine the resonant frequency of a tuned circuit whose inductance is 150 MicroHenrys (μH) and the capacitance is 150 Picofard (pF)
1. 1.000 MHz
2. 1.061 MHz
3. 1.131 MHz
4. 1.456 MHz
An LC circuit is also called a tank circuit, tuned circuit or resonant circuit, is an electric circuit built with a capacitor (C) and an inductor (L) connected together. These circuits are used for producing signals at a particular frequency or accepting a signal from a more composite signal at a particular frequency. [Information]
1. A series resonant circuit provides voltage magnification.
2. A parallel resonant circuit provides current magnification.
3. The most common application of tank circuits is tuning radio transmitters and receivers. For example, when we tune a radio to a particular station, the LC circuits are set at resonance for that particular carrier frequency.
In a series resonant circuit at resonance, the circuit has: [Information]
1. low impedance
2. Acceptor circuit : as a series resonance circuit only functions on resonant frequency, this type of circuit is also known as an Acceptor Circuit because at resonance, the impedance of the circuit is at its minimum so easily accepts the current whose frequency is equal to its resonant frequency.
3. Series resonance frequency happens when reactances are equal.
  Inductive reactance (XL) = Capacitive reactance (XC)
4. An RLC circuit is an electrical circuit consisting of a resistor (R), an inductor (L), and a capacitor (C), connected in series or in parallel.
In a parallel-resonant circuit at resonance, the circuit has a: [Information]
1. Very high impedance at resonance
2. Rejector circuit : as a parallel resonance circuit only functions on resonant frequency, this type of circuit is also known as an Rejector Circuit because at resonance, the impedance of the circuit is at its maximum thereby suppressing or rejecting the current whose frequency is equal to its resonant frequency.
Three 1.5 volt DC batteries connected in series, the total voltage is ___
1. 3.0 volts
2. 4.5 volts
3. 1.5 volts
4. 2.75 volts
What is a good source of DC supply ?
1. Water
2. Rubber
3. Battery
4. Glass
What device or instrument is used to measure voltage in a circuit ?
1. Spectrum Analyser
2. ODTR
3. Voltmeter
4. Thermometer
What device or instrument is used to measure current in a circuit ?
1. ODTR
2. Ammeter
3. Ohmeter
4. Spectrum Analyser
What device or instrument is used to measure resistance in a circuit ?
1. Ohmeter
2. Voltmeter
3. Thermometer
4. Ammeter
How must a voltmeter be connected in order to measure the voltage of a component in a curcuit ?
1. Series to the component
2. Parallel to the component
3. Mesh to the component
4. None of the above
How must a ammeter be connected in order to measure the current of a component in a circuit ?
1. Parallel to the component
2. Mesh to the component
3. Series to the component
4. None of the above
What electric value remains constant in a series circuit ?
1. Current
2. Voltage
3. Resistance
4. Inductance
What electric value remains constant in a parallel circuit ?
1. Current
2. Resistance
3. Capacitance
4. Voltage
The diameter of a copper wire is halved. Its resistance is ?
1. increase two times
2. increase three times
3. increase four times
4. increase six times
What is a good conductor of electricity ?
1. Glass
2. Rubber
3. Gold
4. Plastic
What is a good insulator of electricity ?
1. Bronze
2. Silver
3. Plastic
4. Copper
Exponential charge/discharge: [Information]
1. Charge :Capacitor voltage begins at zero and exponentially increases to E (V) volts
2. Charge : If the circuit is a battery, a resistor and a capacitor all in series. The charging of the capacitor is slowing down, because of the rising voltage.
3. Discharge : If we discharge a capacitor, we find that the charge decreases by half every fixed time interval
4. Discharge : The voltage, current, and charge all decay exponentially during the capacitor discharge.
Smith Chart: [Information]
1. Purpose: Assisting in solving problems with transmission lines and matching circuits
2. Can be used to determine :Impedance and SWR values in transmission lines
3. Smith Charts are useful to determine feedline line length required to match a load to a radio transmitter.
4. If the impedances aren't matched, maximum power will not be delivered
Wavelength (λ) : Frequency (f) : Speed of Light (c): [Information]
1. Wavelength (λ) : is the distance between two identical adjacent points in a wave. It is typically measured between two easily identifiable points, such as two adjacent crests or troughs in a waveform in Meters (m)
  
  Frequency (f) : measures the number of times something occurs in a specific amount of time in Hertz (Hz)
  
  The speed of light (c) in vacuum exact value is defined as 299,792,458 metres per second (approximately 300,000,000 m/s (meters/second)
2. Wavelength = Speed of light / Frequency of the wave.......Frequency in hertz = 300,000,000 / Wavelength in meters (f = c / λ)
  Wavelength in meters = 300,000,000 / Frequency in hertz (λ = c / f)....In some equations c is given as v where v = velocity of a radio wave (speed of light) c = v
3. Frequency 3.7MHz what is the wavelength (λ) ? λ = c / f = 300,000,000 / 3,700,000 = 81.08 meters thus λ = 81.08 meters
  Wavelength is 2 meters what is the frequency ? f = c / λ = 300,000,000 / 2 = 145,000,000 (145 MHz)
4. If f is the frequency of the signal as measured in megahertz (MHz) and the Greek letter lambda λ is the wavelength as measured in meters we can use
  λ = 300/f and f = 300/λ......In the above examples 3.7Mhz in meters = 300 / 3.7 = 81.08 meters and 2 meters in MHz = 300 / 2 = 145 MHz
  
  A useful reminder 30 Mhz in meters = 300 / 30 = 10 meters and 10 meters in MHz = 300 / 10 = 30 MHz
Transformer (Turns Ratio) : [Information]
1. A transformer is a device used to step up/down voltage or current or impedance....
  The ideal transformer is lossless, but wire resistance, core losses, skin effect cause losses
  .... For ideal transformer the power (watts) in the primary windings (input) equals the power in the secondary (output) Pprim = Psec
  ....Step Up or Step down depends on number of turns on primary and secondary.
2. The turns ratio of a transformer describes the number of wire turns on the input (primary) versus the number of turns on the output(secondary).... A 1:1 transformer would have the same number of turns on each coil while a 1:2 transformer would have twice as many on the secondary (Ns) as on the primary (Np) and a 10:1 transformer would have 10 times as many on the primary (Np) than on the secondary (Ns). Turns Ratio = Np / Ns
3. Example : Volts per Turn. A transformer with a primary winding of 1000 turns and a secondary winding of 100 turns for a turns ratio of 1000:100 or 10:1..... 100 volts applied to the primary will produce a secondary voltage of 10 volts.
4. Q : A transformer operates a 6.0 volt 2 ampere light bulb from its secondary winding. The power consumed by the primary winding is approximately:
  Power in the secondary is I x V = 6.0 x 2 = 12 watts
  Power (watts) in the primary windings (input) equals the power in the secondary (output) Pprim = Psec.
  A : 12 Watts
Root Mean Square (RMS): Peak Value and Average value [Information]
1. The term "RMS" stands for "Root-Mean-Square" is the effective value of a varying (AC) voltage or current......It is the equivalent of a steady DC (constant) value which gives the same effect......Also called the effective or heating value of alternating current, is equivalent to a DC voltage that would provide the same amount of heat generation in a resistor as the AC voltage would if applied to that same resistor......For example, a lamp connected to a 6V RMS AC supply will shine with the same brightness when connected to a steady 6V DC supply......
2. Most multi-meters, either voltmeters or ammeters measure RMS value assuming a pure sinusoidal waveform.Example if the multmeter reads 230 V AC, the RMS value is 230V AC....The peak to peak of 325 AC volts will have RMS value of 325 x 0.707 = 229.7 (230V)
3. The peak to peak value of the RMS measurement is RMS x 1.41. RMS voltage of 230 V AC, peak to peak value would be 230 x 1.41 = 324.3 (325) volts.
4. The average voltage is 0.637 x Peak voltage.The average voltage of 325V peak to peak = 0.637 x 325 = 207 Volts
What is the capacitive reactance of a capacitor whose value is 350 pF, operating on frequency 1200 kHz?
1. 350.7 ohms
2. 450.3 ohms
3. 410.8 ohms
4. 378.9 ohms
A resistor with color bands red, green and orange has a value equal to:
1. 15 ohms
2. 159 ohms
3. 250000 ohms (25k ohms)
4. 2500 ohms (2.5k ohms)
What symbol denotes the positive polarity of a battery ?
1. Slash sign (/)
2. Plus sign (+)
3. X sign (x)
4. Minus sign (-)
What symbol denotes the negative polarity of a battery ?
1. Slash sign (/)
2. X sign (x)
3. Plus sign (+)
4. Minus sign (-)
What wire color often connects to the positive polarity of a battery ?
1. Yellow
2. Blue
3. Red
4. Black
What wire color often connects to the negative polarity of a battery ?
1. Yellow
2. Red
3. Blue
4. Black
Impedance Matching : [Information]
1. Impedance matching is the practice of designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize the power transfer or minimize signal reflection from the load.
2. Impedance matching: Allows transfer of the radio frequency energy from a generator (transmitter) to a load (antenna) through transmission lines with zero or minimum power loss.
Three 1.5 volt DC batteries connected in parallel, the total voltage is ___
1. 2.5 volts
2. 3 volts
3. 1.5 volts
4. 4,5 volts
What electrical value can be concluded if one reads 5 Amperes on a component ?
1. Resistive value
2. Power value
3. Current value
4. Voltage value
What is the total inductance of 2 inductors (Microhenries) - valued at 20 µH each and are connected in parallel ?
1. 40 µH
2. 30 µH
3. 20 µH
4. 10 µH
What is the total inductance of 3 inductors (Millihenries) connected in series with the following values : 3 mH, 5 mH and 22 mH ?
1. 8 mH
2. 10 mH
3. 25 mH
4. 30 mH
What is the total current of a circuit having a voltage of 10V and a total resistance of 10 ohms ?
1. 1A
2. 4A
3. 8A
4. 12A
Voltage (V or E) :
1. Voltage is the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop, enabling them to do work such as illuminating a light.
What electrical value can be concluded if one reads 5 uF (micofarads)on a component ?
1. Voltage value
2. Capacitance value
3. Power value
4. Resiatance value
What electrical value can be concluded if one reads 50 watts on a component ?
1. Voltage value
2. Inductive value
3. Power value
4. Capacitance value
Amateur Radio frequency 430 Mhz - 440 Mhz belongs to what frequency range ?
1. HF
2. VHF
3. UHF
4. EHF
Skin Effect : [Information]
1. is a tendency for alternating current (AC) to flow mostly near the outer surface of an electrical conductor, such as metal wire.The effect becomes more and more apparent as the frequency increases.
2. For alternating currents (AC), the skin effect causes the resistance to increase with increasing frequency.
3. Skin effect is reduced using stranded wires because the strands have limited contact area between each other, and field distribution is better, reducing skin effect
4. DC, there is no change in frequency and hence the inductive reactance is zero! So the current doesn’t find any opposition other than the resistance and it flows completely in the conductor, not just outside!
In AC and RF circuits that is expended in the transmission line on the delivery of power to a complex load load but not consumed at the load can be classfied as:
1. Reactive Power
2. Real Power
3. True Power
4. Imaginary Power
In a condition of series resonance, we can measure a current flow through that is ________
1. Maximum
2. Minimum
3. Zero
4. Fluctating
What electical value is 0.85 mH ?
1. Resitance value
2. Capacitance value
3. Inductance value
4. Power value
Three resistors 4 ohms, 12 ohms, and 18 ohms are connected in series what is the total value ?
1. 10 ohms
2. 16 ohms
3. 34 ohms
4. 46 ohms
What is the power dissipated by a load resistor supplied by 48V source and having a total current of 2A flowing through it ?
1. 48 watts
2. 54 watts
3. 96 Watts
4. 102 watts
What is the voltage across a load dissipating 15W of power and consumes 3A of current ?
1. 8V
2. 1V
3. 5V
4. 12V
What is the current flowing through a load having 12v measurement across it and dissipates 4W of power ?
1. 3A
2. 0.5A
3. 1.5A
4. 0.333A
In what component does one commonly find the resistance value in a circuit ?
1. Capicitor
2. Inductor
3. Transistor
4. Resistor
In what component does one commonly find the inductance value in a circuit ?
1. Inductor
2. Capacitor
3. Resistor
4. Transformer
On what component does one commonly find the capacitance value in a circuit ?
1. Resistor
2. Capacitor
3. Inductor
4. Diode
What are included in the High Frequency range ?
1. 3 Mhz - 30 Mhz
2. 30 Mhz - 300 Mhz
3. 300 Mhz - 3000 Mhz
4. 3 Ghz - 30 Ghz
What are included in the Very High Frequency range ?
1. 3 MHz - 30 MHz
2. 30 MHz - 300 MHz
3. 300 MHz - 3000 MHz
4. 3 GHz - 30 GHz
What are included in the Ultra High High Frequency range ?
1. 3 MHz - 30 MHz
2. 30 MHz - 300 MHz
3. 300 MHz - 3000 MHz
4. 3 GHz - 30 GHz
What is another way of writing 3000 Mhz ?
1. 3 GHz
2. 30 GHz
3. 3 THz
4. 30 THz
Time Constant : RC (Resistor - Capacitor) and RL (Resistor - Inductor) circuits [Information]
1. RC : The time constant (in seconds) of an RC circuit, is equal to the product of the circuit resistance (in ohms) and the circuit capacitance (in farads).
2. RC : A resistor–capacitor circuit (RC circuit), or RC filter or RC network, is an electric circuit composed of resistors and capacitors driven by a voltage or current source. A first order RC circuit is composed of one resistor and one capacitor and is the simplest type of RC circuit.
3. RL : The time required for the current flowing in the LR series circuit to reach its maximum steady state value is equivalent to about 5 time constants or 5τ. This time constant τ, is measured by τ = L/R, in seconds, where R is the value of the resistor in ohms and L is the value of the inductor in Henries.
What does HF represent in reference to frequency ranges ?
1. High Fidelity
2. Henry and Farad
3. High Frequency
4. None of the above
What does VHF represent in reference to frequency ranges ?
1. Very High Frequency
2. Variable High Frequency
3. Very High Fidelity
4. Variable High Fidelity
Capactor : Electrolytic Capacitor : [Information]
1. Capacitor a device used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator...The voltage rating on a capacitor is the maximum amount of voltage that a capacitor can safely be exposed to and can store.
2. Capacitor : The standard unit of capacitance is the farad (F).... This is a large unit; more common units are the microfarad, abbreviated µF and the picofarad, abbreviated pF.
3. Electrolytic Capacitor is a polarized capacitor whose anode or positive(+) plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor.
4. Electrolytic capacitors are often marked with a stripe. That stripe indicates the NEGATIVE (-) lead. If it's an axial leaded capacitor (leads come out of opposite ends of the capacitor), the stripe may be accompanied by an arrow that points to the negative lead.
What is another way of writing 1 kilowatt ?
1. 1000 watts
2. 100 watts
3. 1000 ohms
4. 1000 volts
What is another way of writing 470 kilo-ohms ?
1. 47,000 ohms
2. 470 ohms
3. 470,000 ohms
4. 4,700 ohms
What is another way of writing 1 V ?
1. 1 kilo - volt
2. 1 mega - volt
3. 1000 milli - volt
4. 100 milli - volts
In what frequency range does the 7.095 MHz A3J signal belong to ?
1. VHF
2. HF
3. UHF
4. EHF
Two identical capacitors are connected in series. If the value of the capacitors is 4 µf each. What is the total capacitance ?
1. 2 µf
2. 4 µf
3. 8 µf
4. 16 µf
Two capacitors rated 10 F each are connected in parallel, the resultant capacitance is______
1. 5 F
2. 10 F
3. 20 F
4. 40 F
Three identical capacitors rated at 120 µf each are connected in series. What is there equivelant capacitance ?
1. 10 µf
2. 20 µf
3. 40 µf
4. 60 µf
Two resistors valued at 3 and 6 ohms respectively are connected in parallel. What is the resultant resistance ?
1. 1 ohm
2. 2 ohm
3. 3 ohm
4. 4 ohm
When the resistance of a copper wire is increase in diameter ? The resistance is ________
1. reduced
2. stays the same
3. increased
4. zero
A 12 v car battery is connected across a 120 ohm load. What is the current that flows through the load ?
1. 2 volts
2. 2 amps
3. 0.1A (100 mA)
4. 1 watt
1 Micohenry is equal to ____
1. 0.0001 H
2. 0.00001 H
3. 0.001 H
4. 0.000001 H
How many micofarads are there in 1 farad ?
1. 1 hundred
2. 1 thousand
3. 1 million
4. None of the above
For maximum current, dry cells should be connect in___
1. series
2. parallel
3. parallel and series
4. together
Energy and Power : [Information]
1. Energy : is defined as the amount of work that can be performed by force. Energy is 'watt-hour' and can be stored.
2. Power : is defined as the rate at which work is performed. Power is 'watt' and cannot be stored
If we increase by two times the resistance of a circuit whose voltage is kept constant. What will happen to the current ?
1. the current will be reduced to zero
2. the current will double
3. the current will he halved
4. the current will be absorbed
Dry (battery) cells should be connected in series to_____
1. to produce a lower voltage
2. to produce a higher voltage
3. to produce a constant voltage
4. None of the above
Storage batteries are rated in _____
1. voltage - hour
2. ampere - hour
3. capacitance - hour
4. inductance - hour
If the diameter of a wire is doubled ( x 2 ) its resistance becomes a
1. eighth (1/8)
2. half (1/2)
3. quarter (1/4)
4. none of the above
Example of a good electrical insulator _____
1. aluminum
2. tin
3. rubber
4. copper
A example of a good semi conductor______
1. silicon
2. magnesium
3. glass
4. sodium
Prefix PICO means_______
1. 10 million
2. 10 (raised to the positive) 10
3. 10 (raised to the negative) 10
4. 10 billion
Electrical power is measured in______
1. Farads
2. Volts
3. Amps
4. Watts
Current and Voltage Dividers : [Information]
1. Current : Current divides when the resistors are connected in parallel
2. Current : A parallel circuit has two or more paths for current to flow through. Voltage is the same across each component of the parallel circuit. The sum of the currents through each path is equal to the total current that flows from the source.
3. Voltage :The voltage divides when the resistors are connected in series
4. Voltage : The amount by which the voltage drops over across each resistor depends on the relative values of each resistor and the total resistance.
An example of a widely used semi conductor material___
1. germanium
2. silica
3. bromide
4. feldspar
Current (A) : [Information]
1. Current is a flow of electrical charge carriers, usually electrons or electron-deficient atoms. The common symbol for current is the uppercase letter I. Electric current can be either direct or alternating.
2. One ampere of current is defined as one coulomb of electrical charge moving past a unique point in a second.
3. The coulomb (symbol: C) is equivalent to the charge of approximately 6.242×10 to the 18th
4. Effect of current flow ?
  1) Heat is dissipated : Heat is generated. If the current is small then the amount of heat generated is likely to be very small and may not be noticed. However if the current is larger then it is possible that a noticeable amount of heat is generated.
  2) Magnetic effect: A magnetic field is built up around the conductor. If a current is flowing in conductor then it is possible to detect this by placing a compass close to a wire carrying a reasonably large direct current, the compass needle can be seen to be deflect.
A ____ is an instrument that measures resistance less than one ohm.
1. multi meter
2. grid dip meter
3. Wheatstone bridge
4. closed circuit
Unit of conductance ?
1. Amps
2. Ohms
3. Siemens
4. Watts
The main characteristic of a diode is:
1. high resistance
2. low conductivity
3. reverse bias
4. current flows in one direction
What is the value of the resistance having the color bands : green - green - orange ?
1. 55 Kohms
2. 55 ohm
3. 550 ohms
4. 5500 ohms
What is the frequency of operation when wavelength of the radio signal is 3 meters long ?
1. 100 mhz
2. 200 mhz
3. 300 mhz
4. 400 mhz
To convert wavelength of 10 Meters to frequency in MHz
1. 300 + 10 Meters = 310 MHz
2. 300 x 10 Meters = 3000 MHz
3. 300 / 10 Meters = 30 MHz
4. 300 - 10 Meters = 270 MHz
In order to protect the station from lightning, all antenna system and equipment should be_______
1. terminated
2. grounded
3. painted
4. secured
The use of a key-operated switch is recommended in order to _____
1. prevent operation of unauthorized persons
2. conserve electricity
3. prevent unwanted radiation
4. extend equipment life
The circuit element that opposes any change in voltage is____
1. Transistor
2. Resistor
3. Inductor
4. Capacitor
The logarithm of the ratio of the output power over the input power _____
1. Impedance
2. Reactance
3. Conductance
4. Bel
A series circuit consists of an inductance of 2 H and a capacitance of 400 uF. What is the resonant frequency?
1. 2.3 Hz
2. 5.6 Hz
3. 7.1 Hz
4. 8.9 Hz
Mega is ______
1. 100
2. 1000
3. 10,000
4. 1,000,000
The circuit element that opposes any change in current is_____
1. Resistor
2. Fuse
3. Inductor
4. Capacitor
Electro Magnet : [Information]
1. An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets usually consist of wire wound into a coil. The poles of an electromagnet can be reversed by reversing the flow of electricity.
Power Factor : [Information]
1. The power factor is the ratio between Real Power and Apparent Power. It's expressed as a value between -1 and 1 and can be either inductive (lagging) or capacitive (leading). If the power factor is 1, then all of the, power supplied is being used for productive work and this is called 'unity'.
Thevenin's Theorem [Information]
1. Thevenin's Theorem states that “Any linear circuit containing several voltages and resistances can be replaced by just one single voltage in series with a single resistance connected across the load“.
2. Thevenin theorem is an analytical method used to change a complex circuit into a simple equivalent circuit consisting of a single resistance in series with a source voltage.
What is the difference between an insulator, conductor and semiconductor of electricity? [Information]
1. Conductors let electricity pass through them easily....most metals are good electrical conductors
2. Insulators do not allow electricity to pass through them... most nonmetals are not good conductors of electricity.
3. Semiconductor material have an resistance levels between those of a conductor and an insulator......Examples of semiconductor materials are germanium, selenium, and silicon.
73 de 4F3EW - 7 November 2021