Flashcards
Electronics Flashcards
Cards in this deck (21)
- 1What is the resistance?1.5K Ohms
10% tolerance - 2What does a rectifier do?A rectifier is an electronic device or circuit that converts alternating current (AC) into direct current (DC). In other words, it rectifies the voltage, changing it from a waveform that periodically switches polarity to a steady voltage with a consistent polarity. This is achieved by allowing current to flow in only one direction through the circuit.
- 3What is the resistance?25 Ohms
5% tolerance
- 4What is the resistance?2.5 Ohms - 10% tolerance
3rd stripe = gold... multiply 1st 2 digits by 0.1. RG = 25 * 0.1 = 2.5
3rd stripe = Silver = * by 0.01
- 5What is the resistance?365 Ohms - 0.5% tolerance.
4th digit = multiplier
5 digit = tolerance
Brown = +- 1%, Red = +-2%, Green = +-0.5%, Blue = +-0.25%, Violet = +-0.1%
- 6This is the symbol for what?A variable resistor
- 7What is the purpose of a rheostat?A rheostat is used to vary the amount of current. R1 is 5 ohms and the rheostat R 2 varies from 0 to 5. So the total varies between 5 and 10 ohms total.
- 8How do you use a Potentiometer as a Rheostat?Connect one end of the control (middle) and variable arm (ends). The 3rd terminal is open / unused / floating / not connected.
Another way is to connect the unused terminal to the center terminal which is preferred as there is no floating resistance. - 9How do you calculate the maximum voltage a resistor can handle? What is the maximum voltage for a 1/2-Watt, 1000 Ohm resistor?(0.5*1000)^0.5 = ~22.36
- 10This is the symbol for what?A Potentiometer.
- 11If a 12-Ohm resistor is carrying a current of 2.5 Amps, how much is its voltage?V = I*R.
12*2.5 = 30 Volts - 12How do you calculate power? i.e. what are the formulas?P = V * I
P = I^2 * R
P = V^2 / R - 13How many watts are there in 1 Horsepower?746 W = 1 HP = 550 ft-lb/s
1 HP = roughly 3/4 of 1 KW - 14What is the formula for Power?Power = Work / Time
Also, 1W = 1 Joule per Second
1W = 1 Volt-Amp
1A (includes time) = 1 Coulomb / S - 15What is one eV (electron volt)? How many electron volts are in 1 Joule?1 eV is the amount of work required to move 1 electron between 2 points that have a potential difference of 1 volt.
6.25*10^18 electrons = 1 joule - 16How much current is needed for a 600-W, 120-V toaster?I = P / V
600 / 120 = 5 Amps - 17How much current is needed for a 24-Ohm Resistor that dissipates 600 W?I = (P/R)^0.5
I = (600 / 24)^0.5
I = 5 Amps - 18What is the resistance of a 100 Watt lightbulb with a 120 Volt source?R = V^2 / P
R = 120 * 120 / 100
R = 144 Ohms - 19How do you calculate the maximum voltage a resistor can handle?
- 20What are the two main types of transistors?Bipolar Junction Transistors (BJT)
Field Effect Transistors (FET)
MOSFET = Metal Oxide S FET - 21What is the difference between a transistor and a vacuum tube?A transistor amplifies current and a vacuum tube amplifies voltage
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- None Electronics Flashcards on Electronics Flashcards, created by William Bloodworth on 23/10/2023.
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- William Bloodworth
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