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Electronics Engineering
Electronics Engineering is a branch of engineering that deals with practical applications of electronic components, devices, systems, or equipment. Electronics are devices that operate on low voltage sources, as in electron tubes, transistors, integrated circuits, and printed circuit boards and use electricity as part of its driving force.
24,372 Questions
What is the difference between half subtractor and full subtractor?
simply by complementing x input before applying to and gate for generating carry
What is voltage potential betweei positive to earth?
By saying 'positive', you appear to be describing a d.c. system. In which case it depends entirely on the potential difference of the source and how it is earthed. If you are describing an a.c. system, then you presumably mean 'line', rather than 'positive', then -again- it depends on the potential difference of the source and how it is earthed -e.g. in the UK, the potential of the line, measured with respect to earth, should be close to the nominal value of 230 V.
Incidentally, there is no such thing as 'voltage potential'. 'Voltage' is synonymous with 'potential difference', not'potential'. So, when you say 'voltage potential', it's the same as saying 'potential difference potential' which, I think you will agree, doesn't make any sense!
How do you reverse polarity on ac motor?
Reversing polarity is not possible with an ac motor. Some do have wiring that will allow you to change rotation. The type and model of the motor can tell you if it is reversible.
How does a ujt relaxation oscillator work?
The operation of the circuit is as follows: C1 charges through R1 until the voltage across it reaches the peak point. The emitter current then rises rapidly, discharging C1 through the base 1 region and R3. The sudden rise of current through R3 produces the voltage pulse. When the current falls to IV the UJT switches off and the cycle is repeated.
12 flip-flops in series can divide by 4096. 20.48 MHz divided by 4096 is 5 KHz.
Other division factors are possible, but 4096 is the maximum.
Why emitter base junction is always forward biased for normal operation of transistor?
The easy answer - it's not always forward biased. Both it, and the collector-base junction, must be forward biased to pass current through to the collector. Whether NPN or PNP the relative bias (voltage) on the base determines the conduction from emitter to collector. NPN: if the base is positive, relative to the collector and emmiter, the transistor conducts. PNP: if the base is negative, relative to the collector and emmitter, it conducts.
For either transistor arrangement, draw two diodes connected either by their anodes or by their cathodes. The base is the region between them. In an NPN, a positive voltage on the anode, compared the to the cathode(s), will forward bias both, allowing current to flow. The same applies to a PNP with a relative negative voltage being the 'switch', turning both on.
bob
02/07/2009
The first paragraph is incorrect. The collector-base junction will be reverse biased for normal operation. The only time an NPN base will be biased more positively than the collector is when it's operating in saturation mode.
The second paragraph is also misleading. It implies that current flows (for NPN) from the collector to the base and then from the base to the emitter. Emitter current is base current plus collector current. The collector-base junction is normally reverse biased, so little current would flow.
Here's a link with relevant info: http://www.nationmaster.com/encyclopedia/Bipolar-junction-transistors
Dennis
The device used to deenergize circuits automatically when a very small ground-fault flows is the?
Ground Fault Circuit Interrupter (GFCI).
List some conductors made of metal?
Anything made of a metal or metal alloy will be a conductor. The most common are copper (indoor wiring) and aluminum (power lines and transmission cables).
If the input frequency to a full wave rectifier is 400Hz what is the ripple frequency?
twice the frequency that is rectified.
Analog signal vs digital signal?
A: Analogue is a signal DC with varying amplitudes. Digital is a state defined as true or false or machine language '1' '0' Digital must change states to supply information while analogue it has only to change amplitude
What measurement can vary with AC current by not DC current?
HZ.
Hertz is the name given to the frequency of the alternating circuit.
Direct current (DC) has no frequency since one wire is always positive and the other is always negative; but AC (Alternating Current) rapidly changes polarity, and does so at a rate that is defined by HZ.
Difference between register and flip flop?
Answer: A flip flop switches one connection between two points, a latch lock a connection, if you have a push to make press button and you press it, the circuit wil turn on but when you release the button it will turn off again, if you have a latch in the circuit then you can release the button and it will stay on.
4 resistors were connected in parallel it yields 5A of current from 220V supply.
What are the various types of Semiconductor Packaging Market?
The global semiconductor packaging market size is projected to expand at a considerable CAGR during the forecast period, 2021–2028. The growth of the market is attributed to the increasing demand for consumer electronics in emerging economies.
Resistance:
Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law:
Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms)
where:
Voltage [V]= the energy lost across an component (voltage measured in volts).
Current [I] = the charge (electrons) flowing through an component (current measured in Amps).
Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your hand steady.
When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life.
Resistor:
The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by:
P = V x I (Power = Voltage x Current) (power measured in watts)
There are also many types of resistors including:
· Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo).
· Thermistor - changes resistance when the temperature changes (used in a thermostat).
· Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights).
Resistor Example:
An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow... the LED would blow up. We need to use a resistor to limit the voltage and current.
But which value of resistance should the have resistor? Uses ohms law:
R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms
(Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED)
But which value of power should the resistor be capable of handling?
P = V x I = (12.0 - 2.0) / 0.02 = 0.2 Watts
ANSWER: HOW ELSE WE BE ABLE TO AMPLIFY A SIGNAL that is the answer.
What is difference between pulse width modulation and pulse position modulation?
Frequency modulation, as the name suggests, modulates the carrier by changing the frequency of the signal emitted.
Pulse width modulation, changes the on-time of a square wave, but leaves the frequency of the carrier wave unchanged.
So, in frequency modulation, the frequency will vary between, say, 80kHz and 120kHz with a constant power level, but in pulse width modulation, the frequency will stay at 100kHz, but the on-time (the length of each pulse) will vary, hence the power level will vary accordingly.
What are active and passive transducers?
An example of a passive transducer is differential transformers. The reason why is because passive transducers require an external power supply to operate.
What Is significance of schottky transistor in TTL gates?
A diode in general lets current flow more in one direction than the other. This can be used in many configurations in an electronic circuit, with one of the more common uses in memory and decision making circuits. With more of our electronic devices running on batteries, manufacturing processes are finally realizing that people will probably buy the device that has a longer battery life over other considerations. Wikipedia contributors contend that the metal-semiconductor junction switches faster and operates at lower voltage.
What is the current in a 10V circuit if the resistance is 2Ω?
If a resistor has a current of 2 amperes when connected to a single battery, connecting a second identical battery in parallel with the first will not change the current through the resistor.
This is because the voltage across the resistor will not change. Yes, the current capacity of the battery (pair) will double, but the voltage will not change.
The exception is if the battery does not have the capacity to supply 2 amperes without sagging in output voltage. In this case, adding the second battery will slightly increase the current through the resistor.
(By the way, without some kind of equalizing circuit, it is not a good idea to connect batteries in parallel. This is because slight differences in voltage could create substantial current flows through the batteries, and possibly damage, fire, and/or explosion.)
Voltage is a build up of electrons at one location relative to another location. To form a voltage gradient (difference), you need to somehow build up electrons at one location, or remove electrons from one location. Shuffling your feet on a thick carpet can do this!
Is there such a thing as 115V 3 phase?
No!
The concept of three phase alternating electricity refers to the relational phase differential of three alternating current single phase sine waves, each displaced 120 degrees of phase angle from the other.
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Addetion:
still the is a three wire DC transmission system.
usually DC transmission used for several resone but the most know one is when the transmission line is longer than 600 km
Are the voltage and current in phase in a circuit of pure resistance?
Assuming that by the question you mean a circuit with a resistance, but no inductance, or capacitance, then yes, the voltage and current will remain in phase.
Reasoning:
The formula V = IR or... Voltage is equal to Current multiplied by Resistance, is (should be!) well known by school students, however this formula assumes that voltage and current are each constants.
This formula can be extended to apply to voltages and currents that vary with time, as in the following equation:
V(t) = I(t) R
Since R will be a constant resistance expressed in Ohms (or more formally, an impedance that contains no imaginary part: a real number), there is nothing in the formula that could introduce a phase shift.
(See the related link below for a wikipedia article on impedance.)
