Electronics Engineering

A pre-amp is a type of amplifier used in sound systems. It usually amplifies the signals coming from microphones or low amplitude signals coming from any other sources. The pre-amplified signals can then be amplified to a greater extent when the signals are sent to the main amplifier. Because some microphones are low voltage or are wireless the signals are weak compared to older style microphones.

Taking the question at face value, the internal resistances will be treated like "real" resistors in the circuit. That means we have 3 batteries of 1.5 volts each connected in series with their 2 ohms + 2 ohms + 2 ohms of internal risistance, or 6 ohms of internal resistance. The 6 ohms of internal resistance acts in series with the 44 ohms of resistance stated as the value of the resistor. The total resistance is simply the sum of the two, or 6 ohms + 44 ohms or 50 ohms of total resistance. The batteries are connected in series, and their individual voltages are added to find total applied voltage. That means 1.5 volts + 1.5 volts + 1.5 volts or 4.5 volts will be the total applied voltage. Total current in the circuit (and through our 44 ohm resistor) will be the voltage applied divided by the resistance ( I = E / R), which, in this case, is 4.5 volts / 50 ohms which equals 0.07 amps. That's 7/100ths of an amp, or, in electronics speak, 70/1000ths of an amp, or 70 milliamps, or 70mA of current. The circuit is a series circuit, and that current, the total circuit current, will be flowing through each and every component of the circuit. That's what a series circuit means.

Yes, germanium was the only material used in transistors from when they were invented in 1947 until 1954 when the first successful silicon transistor was made.

However the use of germanium still dominated transistors until the silicon mesa transistor was made commercially available by Fairchild Semiconductor in 1958. Development of the silicon planar transistor by Fairchild Semiconductor the next year ultimately made the integrated circuit possible.

While almost all transistors today are silicon, there are still uses for germanium transistors so a few types are still made.

Convection is the process that causes warm air to rise and cold air to sink. As such, the winds caused by this process are called convection currents.

These are two incompatible units. Ignoring the kilo- prefix (1000), we have V (Volts) and VA (Volt-Amps). VA is a rating of power, typically on transformers and related equipment. So while you cannot _convert_ from KV to KVA, you can calculate one from the other. For example, a 240V transformer rated to supply 100A of current would be a (240*100 = 24000) 24kVA transformer. Power = Volts * Amps.

The quoted value is usually RMS value, i.e it is lesser than the peak value of the voltage, therefore the peak value is sqrt(2) times the quoted value. (it is a sine wave)

A transformer. it steps up / down voltage, and steps down / up current.

Using the formula I = W/E, the current of the circuit will be 6.8 amps. As long as the wire is at least a #14 and is protected by a 15 amp two pole breaker There will be no problem. Just make sure that the specifications on the 1500 watt device clearly show that the voltage range is 220 - 240 volts.

It certainly can, but it would depend on the fuse rating and existing load on the circuit.

a topic which is about for electronics

This Easy to build PIC based IC tester is very easy to make and highly reliable.This IC tester can successfully check the most of the IC's we are using in our normal project constructions such as TTL,74,74F,CMOS 4000 series.This could be very useful for the professionals as well as hobbyist.

If you double the voltage in a circuit, the power is quadrupled, assuming the resistance stays the same.

Electron tubes are used to manipulate electronic or electrical signals. They can be employed to convert AC to DC, amplify, attenuate, switch, mix, or generate audio or radio signals. Tubes have been mostly replaced by solid-state devices such as the transistor, but still have some applications in modern electronics.

The resistance of a conductor is directly proportional to its length, hence increasing the length twice will increase the resistance twice as well. Therefore the resistance will be 2*10 = 20 Ohms

can u tell some recent topics in giving the prfesentation in the college related to computer techniques that is recently work..
so that i wl get gud response by college and will help in my placment..

ANSWER:- Kouwenhoven's factors: AC changes direction frequently; it is the current usually supplied by household electrical outlets in the US and Europe. DC flows in the same direction constantly; it is the current supplied by batteries. Defibrillators and cardioverters usually deliver DC current. How AC affects the body depends largely on frequency. Low-frequency (50- to 60-Hz) AC is used in US (60 Hz) and European (50 Hz) households; it can be more dangerous than high-frequency AC and is 3 to 5 times more dangerous than DC of the same voltage and amperage. Low-frequency AC produces extended muscle contraction (tetany), which may freeze the hand to the current's source, prolonging exposure. DC is most likely to cause a single convulsive contraction, which often forces the victim away from the current's source.

As per IEEE std. 80 as well.....

let go current is 16mA for AC and 75mA for DC....

So there is nothing like AC will throw you off and DC will hold you off....

Question itself wrong....

It doesn't. You can make a differential amplifier with a single power supply.

With a new kind of wind turbine called a vertical axis wind turbine (VAWT) that can produce electricity in winds as low as 5 mph.

Well, you do use a multimeter to measure it, but not directly. You need

at least one other thing besides the multimeter and the dry cell. Here's

a simple way to do it:

-- Take a resistor. With the meter set to measure resistance,

measure the resistor's value. Call that 'R'.

-- With the meter set to measure voltage, measure the voltage

of the dry cell. Call it 'V1'.

-- Connect the resistor across the dry cell. Measure the dry cell's

voltage again. Call it 'V2 ' this time . V2 will be less than V1 .

The internal resistance of the dry cell is

R times (V1 - V2) / V2

Using Ohms Law: V = I x R, where V (Voltage), I (Current), and R (Resistance). re-arranging: V/R = I Therefore if you double both the Voltage and the Resistance, the current remains unchanged.
Current = Voltage / Resistance. If both resistance and voltage double the current remains the same.

It's very simple: If you use a material with lower strength or hardness, your entire project could collapse on itself. I'm reminded of a US bridge in which a contractor used the wrong metal for metal struts connecting the cement beams. The bridge collapsed, throwing dozens of vehicles into an icy river; many people died. The bridge tore itself apart under tons of weight, simply because the wrong strength of metal was used.

Ohm's law states that I = V/R, where I is current in amperes, V is difference potential in volts, and R is resistance in ohms. If I goes up, by relation, either V increases or R drops or both occur. Correspondingly, R = V/I, so if V stays static and I increases, R must decrease.?æ

due to minority carriers

orange-orange-orange

A walkie-talkie is a hand-held portable, bi-directional radio transceiver. The first walkie-talkies were developed for military use. Major characteristics include a half-duplex channel (only one radio transmits at a time, though any number can listen) and a push-to-talk switch that starts transmission. The typical physical format looks somewhat like a telephone handset, possibly slightly larger but still a single unit, with an antenna sticking out of the top. Where a phone's earpiece is only loud enough to be heard by the user, a walkie-talkie's built-in speaker can be heard by the user and those in his immediate vicinity. The first radio receiver/transmitter to be nick-named "Walkie-Talkie" was the backpacked Motorola SCR-300, created by an engineering team in 1940 at the Galvin Manufacturing Company (fore-runner of Motorola). The team consisted of Dan Noble, who conceived of the design using FM technology, Henryk Magnuski who was the principal RF engineer, Marion Bond, Lloyd Morris, and Bill Vogel. Motorola also produced the hand-held AM SCR-536 radio during the war, and it was called the "Handie-Talkie" (HT). Donald L. Hings also worked on the early technology behind the walkie-talkie between 1934 and 1941, and is sometimes said to actually have invented it. A Hand-held transceivers became valuable communication tools for police, emergency services, and industrial and commercial users, using frequencies assigned for these services. Walkie-talkies are also popular with some amateur radio operators, operating with an amateur radio license in several different frequency bands. Since even a powerful commercial walkie-talkie is limited to a few watts of power output and a small antenna (the physical size of the package limits both battery capacity and antenna size), hand-held communication range is typically quite short, with a typical range not exceeding the line-of-sight distance to the horizon in open areas, and much less in built-up areas, within buildings, or underground. Many radio services permit the use of a repeater which is located at some high point within the desired coverage area. The repeater listens on one frequency and retransmits on another, so that reliable hand-held to hand-held unit range can be extended to a few score miles (kilometers) or further, using repeaters linked together. Low-power versions, exempt from licence requirements, are also popular children's toys. Prior to the change of CB radio from licensed to un-licensed status, the typical toy walkie-talkie available in retail stores in North America was limited to 100 milliwatts of power on transmit and the 27 MHz citizens' band channels using AM amplitude modulation only. Later toy walkie-talkies operated in the 49 MHz band, some with FM (frequency modulation), shared with cordless phones and baby monitors. The lowest cost devices are very crude electronically, may employ superregenerative receivers, and may lack even a volume control, but they may have elaborate packaging. Unlike more costly units,low-cost toy walkie-talkies may not have separate microphones and speakers; the receiver's speaker typically doubles as a microphone while in transmit mode. The personal walkie-talkie has now become popular again with the new U.S. Family Radio Service and similar unlicensed services in other countries. While FRS walkie-talkies are also sometimes used as toys because mass-production makes them low cost, they have proper superheterodyne receivers and are a useful communication tool for both business and personal use. Operation in the Family Radio Service is restricted to walkie talkies limited to 500 milliwatts of effective RF power. Some FRS models also include the surrounding GMRS channels, which require a license. Trivia Handie Talkie refers to Mototorla portable products only. According to the US Patent and Trademark Office, Handie Talkie became a trademark of Motorola, Inc. on May 22, 1951. The application was filed June 24, 1948 and the trademark registration number is 71560123. The abbreviation HT is commonly used to refer to portable handheld ham radios (from any manufacturer) in the UHF and VHF ranges. A walkie-talkie is called "talkie-walkie" in French.