Electronics Engineering

Resistance of stator winding is the resistance of the copper conductors being used for building the windings of three separate phases, i.e. R-Y-B. These windings are marked like U1-U2, V1-V2 & W1-W2 at the motor terminals (6 nos.) for the three phases, i.e. R-Y-B respectively. We have simply to measure the resistance of each winding by using a multimeter by connecting the terminals (2 no.) to U1 & U2 and so on.

The resistance should be in ohms not milliamps [amps is form of measuring current not resistance] milliamps to microamps in case of large motors, it may be in amps in case of small sized motors. But resistance of each winding should be nearly same to each other. This shows the electrical balance among windings & also proves the healthiness of the winding.

22ma. E=R/I

3 Kv = 3,000 volts.

The ratio of RB1 to RBBO is the intrinsic standoff ratio. It is the standoff voltage ratio to the power supply voltage.

Unipolar full step Stepper motor: _ _

INPUT SEQUENCE: X Y X Y

1 1 0 0

0 1 1 0

0 0 1 1

1 0 0 1

8255 CONTROL WORD: 1 0 0 0 0 0 0 0 =80H

PROGRAM:

MVI A, 80

OUT port B

START MVI A, FC

OUT port A

CALL DELAY

MVI A, F6

OUT port A

CALL DELAY

MVI A, F3

OUT port A

CALL DELAY

MVI A, F9

OUT port A

JMP START

DELAY LXI D, 0003

CALL DELAY

RET

A: A circuit to be useful to do work must be stable with the environment and also with reliable circuit performance. A circuit that is allow break into oscillation or other criteria is not stable therefore not much useful.

When we bring a positively charged body towards a negatively charged body the negatively charged particles in the negatively charged body move towards the positively charged particles in the other body i.e an electric charge moves when we bring two bodies of differently charged bodies or the same charges(they repel each other in this case)

A square wave pulse generator is the most commonly used generator. It is mainly used in testing different equipment. It outputs square waves that varies between two levels, with a 50 percent duty cycle.

Electrical signals are either direct current (DC) or alternating current (AC).

For DC signals, information is carried by the existence of a DC level, or it's absence. This is binary signalling, and communicates either a '1' or a '0'.

An AC signal conveys information by either changing one of the three properties that AC signals have:

1) changing the amplitude of the signal (this is amplitude modulation, like an AM radio)

2) changing the frequency (this is frequency modulation, like an FM radio station)

3) changing the phase of the AC signal. This is used in the faster of the old-style computer modems, as well as DSL modems

Conductance is the reciprocal of resistance, and is measured in siemens (S).

So a 5.1 ohm resistor has 1/5.1 conductance,

which is approximately 0.196 078 431 372 549 019 607 843 137 254 9 S.

It must (i) increase, or (ii) decrease, or (iii) stay the same.

If (iii), there's no point in having it at all,

so consider what happens to stage gain at the lowest frequencies, as the capacitor has less and less effect on the circuit.

DC input refers to the direct current electrical input provided to a device or circuit. Unlike alternating current (AC), which periodically reverses direction, DC maintains a constant voltage and direction, making it suitable for many electronic devices, batteries, and power supplies. DC input is commonly used in applications like batteries, solar panels, and electronic circuits where stable voltage is essential.

The color bands show the nominal resistance. The actual resistance is within some percentage (tolerance) of the nominal resistance, so the measured resistance is close to the nominal but not exactly the same. Also resistance varies with factors like temperature and age of the device.

The potential barrier in silicon is higher due to its relatively larger energy bandgap compared to other materials, such as germanium. This bandgap, approximately 1.1 eV for silicon, requires more energy to excite electrons from the valence band to the conduction band, thus creating a larger potential barrier for charge carriers. Additionally, silicon's crystal structure and doping levels influence the height of the potential barrier, affecting charge transport properties in semiconductor devices.

Using a higher voltage reduces power losses during transmission.

• SDH and PDH are two digital hierarchies in which different line speeds (e.g. E1, T1, STM1) are categorized.
• PDH (plesiosynchronous digital hierarchy) was replaced by SDH (synchronous digital hierarchy) due to its drawback in synchronisation where plesio refers to nearlysynchronous.
• E1, T1 and J1 are generally categorized under PDH. STM1, OC3, STM4, OC12 etc. are categorized under SDH.
• E1 is used worldwide nowadays in 2G technologies except North America and Japan (who are using T1 and J1 respectively). It is the line speed of 2Mbps. But how this speed comes along? The derivation is as follows.
• The audio signals were sampled and converted to digital signal at 64kbps, since 1960s for digital transmission of voice calls. When 32 channels (30 assigned for voice channels and 2 channels for framing and signaling), with each having speed of 64kbps are put together (or we call multiplexing), a line speed of E1, i.e. 2Mbps is produced by having 32 x 64kbps = 2.048Mbps.
• T1 line, which transmits at 1.544 Mbps can be interconnected with E1 for international use.
• Having 3 different speeds (E1, T1 and J1), PDH was later replaced by SDH in order to standardize the speed, making only 1 standard speed worldwide, which is STM1 having the speed of 155.52Mbps.

E=sin(Theta);

You need to normalize the equation for the electric field of the half-wavelegnth dipole. recall E=sqrt(ExE*) where E* is the conjugate of the E field.

This is why you only get an eight shaped figure (or infinity symbol) when you plot it. you will get this figure if the dipole is placed in the axis of interest. e.g. if it is in the placed in the x axis, you will get an eighth in the x-y,x-z, but you will get a donut shape in the y-z (no angle to measure)

hope this helps a bit.

operating point of dc load line refers to point where there is no signal either no amplification use to take place as base current is zero(in case of common emitter configuration) and it is represented by Q.......

passive attacks : footprinting, trashing

active attacks : sniffing, social engineering

It's what happens when a battery is about to expire.

there are no good or bad conductor there are conductor ,semiconductor and isolator.

what is communication system explain with block diagram.

The term Microwave is a description of a high frequency radio wave in the range of 1 Gigahertz (One million cycles per second) to 40 gigahertz (40 million cycles per second). Radio waves at this frequency have the tenancy to reflect & refract making them useful for a wide number of applications.

Also since the radio wavelength is related to the frequency (frequency in Hertz divided by the speed of light in metres per second equals wavelength) the aerial size for this band is very small allowing for the use of exotic aerial systems such as dishes.

Dish aerials (antenna) are extremely efficient reflectors for microwave transmitters producing point to point links which can operate over many miles. Unlike High low and medium frequency Transmitters, microwave frequencies are not affected by the ionisation of the gas layers in the atmosphere. Therefore they tend to pass straight through the atmosphere rather than being reflected or refracted back to Earth. This makes them very useful for space communications and radio astronomy.

Microwaves do have some problems though. It is relatively expensive to generate high output at microwave frequencies. Also the nature of microwaves is that they do not pass through solid or grounded objects. This means that rain clouds can block the signal. Also at high power, microwaves excite water molecules, causing them to heat up (this is the principle of the microwave oven). Therefore inappropriate use can be hazardous to health.

Microwave are used to locate ships and planes, track weather systems, and determine the speeds of moving objects. They are the principal carriers of television, telephone, and data transmissions between stations on Earth and between the Earth and satellites.

Reverse voltage is voltage is applied in reverse. Instead of the positive voltage going into the anode lead of a component, it goes into the cathode lead of the component.