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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 differences between cyclo converter and matrix converter?
u refer cycloconverter and matrix converter
Where optical coupler is used?
optical cpupler is used is generally used in 3 instrument
1. optical switches
2. optical weight measurement instrument
3.optical temperature senses
my minor project is optical weight measurement device.
how we measure weight ?
in optical couple r two arm one use as reference arm and another one is experimental arm. we put any weight on experimental arm than light intensity decrease by variation of this intensity we can measure weight.
What is 74ls245 ic with diagram and example?
74245 is a tri state buffer.LS stands for Low-power Schottky
List top core companies of electronics and communication engg?
list of electronic and communication core company in chennai
When did the inventor James T Russell die?
James T. Russell had a huge heart attack and died on the 2nd of July 1973. Don't think so. If we're talking James T. Russell, inventor of compact disc, I worked for him in 1996 and saw him again in 2001. He seemed remarkably animated for someone who died in '73.
Tell you something about op-amp?
An op-amp is a device with two inputs, one inverting and one non-inverting. The output goes to whatever value is needed to make the two inputs the same. This means that, typically, the output is connected to a feedback circuit back into the negative input. This is closed loop, negative feedback operation. Due to the high gain of the op-amp, this configuration makes performance, such as gain and bandwidth, easy to predict.
Where a colpitts oscillator is used?
the Colpitts oscillator , named after the inventor of the circuit , is
characterised by the use of Two Capacitors in series which are then connected in
parallel across the inductor of the resonant circuit for obtaining the required
frequency.
The junction of the two capacitors is used for the positive feedback used
for generating the oscillations.
This circuit is used for High frequency oscillators , mainly due to ease of obtaining
required ratio of the two capacitor values as per the circuit design. Also the two
capacitors in series reduces their total equivalent value , which is not a problem as
in HF circuits as the values and size is comparatively low.
For information , a corresponding Low frequency circuit is called a
Hartley oscillator , also named after its inventor.
This uses a tapped inductor & one capacitor for the resonant circuit, since it is more
easier to fabricate large value tapped inductors , than to use two bulky ( since the
value of capacitors in series is reduced ) capacitors necessary for the equivalent
Colpitts oscillator.
since it stands for voltage ohm meter :) can measure voltage current and resistance
If the devices are in series, then the current from the generator is (40/16) = 2.5 Amp.
If the devices are in parallel, then the current from the generator is (40/3) = (13 and 1/3) Amp.
Why won't a capacitor conduct DC?
capacitor blocks DC, after it finishes charging.
Actually, it resists any CHANGE to DC (ie ac), after it has finished charging. IRT the actual question, current will always flow, as long as there is a closed circuit.
The average 2 mw wind turbine produces a sound eqaul to 45 decibels
What is the use of starter in tube light?
Tube light requires two things to function . Very high starting voltage , and high voltage to continue the operation . The starter is a circuit which breaks at regular intervals . When you break a circuit and start again , high voltage spark takes place . This voltage is further amplified through the choke which is a transformer . Thus at the beginning the starter gives high voltage sparks . Due to this the current begins to flow through the tube and the tube begins to glow. Once the tube starts , the required voltage to sustain is quite low , which is provided by the choke .
If the starter is bad the tube does not start . If the choke is bad or if the gas is low , the tube does not sustain its light .
Fluorescent starters are used in several types of fluorescent lights. The starter is there to help the lamp light. When voltage is applied to the fluorescent lamp, here's what happens:
- The starter (which is simply a timed switch) allows current to flow through the filaments at the ends of the tube.
- The current causes the starter's contacts to heat up and open, thus interrupting the flow of current. The tube lights.
- Since the lighted fluorescent tube has a low resistance, the ballast now serves as a current limiter.
Without the starter, a steady stream of electrons is never created between the two filaments, and the lamp flickers. Without the ballast, the arc is a short circuit between the filaments, and this short circuit contains a lot of current. The current either vaporizes the filaments or causes the bulb to explode.
Was electricity used to supply light and power to US factories?
After about 1890, yes. The use of electricity for lights was far safer than the previous alternative of gas lamps.
Why must do the insulation testing in circuit?
Insulation resistance testing involves applying a voltage across a dielectric, and measuring the resulting current and resistance. However, in order to get a proper reading, any electrical charge still within the system needs to be taken out, so as not to mess with the readings.
How do you tell the difference between AC and DC 3 phase generators and alternators?
The very first thing to do is look at the nameplate. There it will tell you what the voltage is. On a three phase generator there is usually no places to plug any equipment into. Three phase generators usually have the coil ends brought to terminal points in the generators junction box. From a second set of terminals the feeder wires go to the top end of the generators main disconnect breaker. Different voltages can be obtained by positioning jumpers between different terminals within the junction box.
What is difference between amplitude and peak value?
It is the highest value of the amplitude, called the peak value. Scroll down to related links and look at "RMS voltage, peak voltage and peak-to-peak voltage". Look at the figure in the middle below the headline "RMS voltage, peak voltage and peak-to-peak voltage".
What is the Relationship beteen Capacitance and frequency?
The short answer to the question is the capacitive reactance of a capacitor in a DC circuit is infinite.
In a DC circuit, disregarding transient behavior and any leakage effects, a capacitor is effectively an open circuit, and so its reactance is essentially infinite.
Capacitive reactance is calculated as Xc =1/(jwC) where w is the angular frequency in radians per second, w = 2*pi*f, C is in Farads, and f is in Hertz.
With DC, both f and w are zero, and, theoretically, the formula,
Xc =1/(jwC) = limw-->0 [1/(jwC)] becomes infinitely large. In any practical circuit, however, there is always some leakage, so the impedance of the a capacitor will be quite large, on the order of megohms, but still finite.
What is the full form of IGBT?
The full form of igbt is insulated gate bipolar transistor.
it is constructed from the combining of both BJT and PMOSFET.
it has high input impedance and low on - state power loss .
it is free from second break down problem present in bjt...
it is also known as (MOSIGT), (COMFET)...
it is constructed virtualy in the same manner as a power
MOSFET.an IGBT has also thousand of basic structure cells
connected appropritely on a single chip of silicon.
it has a four substrate p,p+,n+,n-. respectively...
p+ substrate is called injection layer because it injects
holes into n- layer .n- layer is called drift region .
thickness of the n- layer determines the voltage blocking
capability of IGBT.
the p layer is called body of the IGBT.
WHERE IT IS USED : it is widely used in medium power
application such as DC and AC motors drives.
UPS SYSTEMS , RELAYS AND CONTACTORS.
In thyristor the gate is triggered the gate is losses its
control. ie if we remove the gate pulse after the thyristor
starts conducting it will not stop.
but in IGBT we can control the Gate. by applying reverse
voltage applied across it .
The Thyristors can not be switched beyond 1kHz where as
IGBTs can be switched upto 25kHz and even to 100KHz with
few soft switching techniques.
The thyristor can carry very high currents order of 3000A
but IGBT carries less current max of 1000A.
Thyristor commutation ,that is switching off is very
difficult. But there are applications of Thyristor with
natural commutation.
The IGBT can be switched on and off like a MOSFET. ie it is
voltage controlled device.
How would you measure a relays contacts resistance?
The voltage drop across a relay coil will be the same as the coil supply voltage. If you are trying to see if the coil is good or not, remove one of the voltage supply leads and check for continuity by using an ohm meter across the coil leads. A reading will tell you that the coil is intact and not open.
If the resistance of the wire is 20 ohms and the voltage between the two ends of the wire is 20 volts,
then the current through the wire is
I = E/R = (40/20) = 2 amperes.
Voltage frequency inverter dc or ac output?
An inverter changes a d.c. input to an a.c. output.
Inverter is a device to change low
volt DC to high volt AC
12 Dc to 220 Ac volt
So many type of inverter of watts
500 watt 1000 watt 5000 watt
