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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 indirect method of FM transmitter?
indirect FM transmitter is the transmitter which indirected connectly to the FM
INDIRECT FM GENERATION
While it is not possible to vary the frequency of a crystal oscillator directly, it is possible to vary its phase. The resulting PM signal can be used to create FM. This is the basis of the Armstrong modulator.
The mathematics required to analyze the Armstrong modulator completely are complex, so we will discuss only the basic circuit operation. An audio signal is passed through a preemphasis network and then an integrator, a special network whose output is the time integral of the input signal. The preemphasized integrated signal is used to phase modulate a crystal oscillator. Mathematically, it can be shown that PM using the integral of the audio signal is identical to FM using the audio signal itself. In this way an FM signal is generated.
The Armstrong modulator cannot produce much deviation, so combination of multipliers and mixers are used to raise the carrier frequency and the deviation. The multipliers are used to multiply the carrier and the deviation. The mixers are used to decrease the carrier, while keeping the deviation constant so that additional multiplier stages can be used to obtain more deviation. It is worth going through an example:
An FM station is authorized to operate at 90.9 MHz, with maximum deviation of 75 KHz. The FM signal is generated with an Armstrong modulator whose output is 500 KHz with a deviation of 15.432 Hz. The modulator output is applied to 3 triplers and a doubler to obtain a frequency of 81 MHz and a deviation of 2.5 KHz. The 81 MHz signal is mixed with a 77.97 MHz signal to produce a 3.03 MHz signal whose deviation is still 2.5 KHz. This signal is fed through a doubler, tripler and quintupler to multiply the carrier to 90.9 MHz and the deviation to 75 KHz.
What is a Protection device for a semiconductor like a IGBT or thyristor?
There are times when you just can not really protect some devices. IGBT's are serious power devices. Circuitry can sense over currents, but possibly not fast enough to save an IGBT. Over sizing them is probably your best bet.
Is it true that the Khoisan will be integrated into the SANDF?
yes it i very true that the khoisan will be intereated into the sandf.
What role does the inductance play if the current increaces in a AC circuit?
i BELIEVE THAT THAT THE CHANGE IN CURRENT WITH THE ACKNOWLEDGEMENT TO TIME wHICH THE FORMULA= VL=is used
If you are talking combinations, without binary number representations, then you are talking about a circuit that has a 1 output when any input is a 0. That is a 3 input NAND gate. If you are talking binary number representation, then you are talking about a circuit that has a 1 output when the inputs are 010, 001, or 000. Use a 3 to 8 decoder, with an OR gate on the low three outputs.
How has transistors change the world?
Enormously!
The predecessor to the transistor was the valve (tube in America). The valve was fragile, ran very hot, physically large and expensive to make.
The transistor (although initially expensive) is robust, efficient, tiny and practically free nowadays (a modern Intel processor contains over 500 million transistor and costs around £100 so a transistor costs 20 millionths of a penny).
So the change to the world has been the possibility of cheap "intelligent" electronics being added to many aspects of life.
Where can you get Fmc 4100 wheel balancer circuit board used?
You can get your FMC/John Bean 2500/4100 or 5800 repaired @ ADER inc.
Why should PCM be preferable to DM for encoding analog signals that represent digital data?
PCM is preferable because of better SNR characteristics.
Transient and steady state response of RC circuit?
To evaluate the transient response of an RC circuit, you start with the steady state just prior to the transient, i.e. just prior to the switch being opened or closed, or just prior to whatever transient event you are modeling. Since you are steady state, assume that capacitors are not present, i.e. they are resistors with infinite impedance. Calculate the voltage and current at each node, using Ohm's law and/or Kirchoff's law and/or Norton/Thevanin equivalents as necessary. Remember that capacitors resist a change in voltage. The equation is dv/dt = i/c. At t=0, assume that each capacitor has the voltage calculated from the initial steady state condition. Initiate the transient and calculate the voltage and current at each node using the initial state differential equation. You can do this analytically, or you can model it in software. If you model, pick an appropriate delta-T, and do a step wise evaluation until the voltages and current settle to their new values. Adjust delta-T to make sure that you are getting consistent results. Just don't go too short, as truncation error can bias the results.
What is unidirectional current?
the current which flows in only one specific direction is called as unidirectional current
Measuring ripple frequency would determine if a diode were open in a bridge rectifier circuit because the ripple frequency is normally twice the input frequency in a functioning full wave bridge rectifier. If one diode were open, the ripple frequency would only be the input frequency.
Note: This is true for single phase or bi-phase operation. Three phase operation is more complex, but still doable - You would expect three times input frequency in normal state, and two times (asymmetric) with one open diode.
Applications of hybrid pi model of bjt?
The BJT remains a device that excels in some applications, such as discrete circuit design, due to the very wide selection of BJT types available, and because of its high transconductance and output resistance compared to MOSFETs. The BJT is also the choice for demanding analog circuits, especially for very-high-frequencyapplications, such as radio-frequency circuits for wireless systems. Bipolar transistors can be combined with MOSFETs in an integrated circuit by using a BiCMOSprocess of wafer fabrication to create circuits that take advantage of the application strengths of both types of transistor.
What is synchronous impedance?
Synchronous impedance is also known as the EMF method. It is a ratio of open circuits to short circuits, when they both are referred to the same field excitation.
What is the function of series pass transistor?
A series pass transistor allows the voltage to pass to the rest of the circuit. The current goes around the part of the circuit like an IC for example, that would be destroyed if too much current were to pass through it.
Series pass transistors allows small voltages and small current parts, to control
higher voltages and currents than they presently cannot do by themselves.
They are used as a hard wired equivalent to binary switches for digital ID purposes along with enabling enabling optional PWB circuitry in various electronics that are not functionally included in a standard product but has the circuitry installed in the PWB.
What are the disadvantages of delta modulation?
1. The bandwidth for transmission of PAM signalis very very large compared to its maximum frequency content.
2. The Amplitude of PAM Pulses varies accordingly to modulated signal. Therefore interference of noise is maximum for the PAM signal and this noise cannot be removed very easily.
3. Since amplitude of PAM signal varies, this also varies the peak power required by the transmitter with modulating signal.
What are the properties desired in a bioelectric amplifier?
- Has a High CMRR value (Common mode rejection ratio) This is to emininate any noise coming from the patient
- High input impedance
- Dosent create noise
- Fast slew rate
- High, variable gain
Manufacturing of IC is known as Fabrication of IC....
it is fabricated from silica(sand)... Inside an IC u can see a small silicon sheet where the actual circuits are imprinted by a process... from that small sheet wires are drawn and fabricated into a IC......
Difference between gsm antenna and microwave antenna?
In GSM mainly using Panel type antennas but in the case of Microwave Antenna using Horn antennas. Microwave anteenas propogate signal straghtly. So line of sight (LOS) is main issue in the case of Microwave antenna, it means that both antennas must be allign in face to face. Microwave antennas are using for link between BTS but GSM antennas are directly link with customers. Antenna Gain also very much difference both cases.
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What is the difference of DC and pulsating DC?
DC: constant current in the forward direction
Pulsating DC: An AC signal which has it's negative components blocked
A: The terminology applies to a VALUE of DC being interrupted by its absence periodically or random
Wave forms of 3 phase fully controlled rectifier for RL load?
for 3 phase r l load phase control rectifier what is the avg value?
What determines the magnitude and polarity of the counter-emf in a dc motor?
the magnitude is decided by the amount of flux, number of conductors, speed of the motor and the type of the winding used.
the polarity is decided by the direction of rotation of the motor and the direction of armature current flowing in the motor.
