One should also be careful about handling the connection: If there is a high voltage (many volts), one can get hurt or even killed by touching the metal connections with the voltage directly.
When the connections are made, the voltmeter shows the voltage. As there is no direct way to access the voltage, voltmeters are designed as special sort of ammeter which can calculate the voltage by assessing the electrical current and applying Ohm's law.
There are two kinds of voltmeters. One kind has a needle, or "pointer", that points to a number that tells the number of volts. This is the kind of voltmeter where one has to be careful about making the positive and negative connections correctly – if the wrong connections are made, the voltmeter can be damaged.
The second kind of voltmeter shows the numbers in a "digital" way, just like digital clocks and calculators. This kind of voltmeter is not damaged from "wrong" connections; instead, they show a negative number.
Also, there are two types of voltmeters, based on the current type: some voltmeters are designed for use in direct current (DC) while others are designed for alternating current (AC). Modern voltmeters can work in both currents.
All voltmeters have an upper limit, or a "maximum number" of volts they can "handle". If a voltmeter is used for bigger voltages than it was made to "handle", it may damage or destroy it.
Because it is important to use the right kind of voltmeter, they are most often made so they can be adjusted to measure all kinds of voltages. Such voltmeters usually have a "knob" or switch that can be set in different ways. If the voltmeter is set in one way, the voltmeter handles voltages up to, for example, 10 volts. If the switch is set in another way, the voltmeter can handle 100 volts, and so on. Inside the voltmeter, the switch usually works by changing resistors in a voltage divider.
In this way, one single voltmeter can be used for a lot of different voltages, large and small. Some modern voltmeters can do this setting all by themselves, one just has to make the connection and not worry about if the voltmeter can handle the voltage. It will automatically find a setting that can handle it.
Today, a voltmeter is usually part of a multimeter, an instrument that can work as both a voltmeter, an ammeter, and usually a few more measuring instruments. These also have switces, used to "tell" the multimeter to "be a voltmeter".
Multimeters often have more than two connections, and part of "telling" the multimeter what to measure (that is, whether to be a voltmeter or an amperemeter) is done by choosing the right two connections. This is explained in the manual for the multimeter, and often shown next to the connection points.
The first type of voltmeters show the voltage using a needle or "pointer" pointing to the number of volts. These voltmeters take energy from the thing being measured to move the needle. Some very weak voltage sources might not have enough energy to move the needle to the right voltage. In that case, such a voltmeter shows too few volts. The voltmeter is not sensitive enough.
One solution to the above problem is to make the needle use as little energy as possible to move. However, there is a limit to how sensitive this kind of voltmeter can be. When vacuum tubes and transistors were invented, it became possible to build electronic amplifiers. By using an amplifier, a voltmeter can measure "very" small voltages from "very" weak sources. Modern voltmeters and multimeters normally have this kind of amplifier in them.
Powderfinger
Powderfinger were a rock band from Brisbane, Australia. The band started in 1989. The band’s members were Bernard Fanning (singer, guitarist), Darren Middleton (guitarist), Ian Haug (guitarist), John Collins (bass), and Jon Coghill (drums).
After some extended plays (EPs) that sold quite well, and making one full album, Powderfinger became popular in Australia with their second album; "Double Allergic". Their third album, "Internationalist", was even more popular and made them celebrities. It sold over 350,000 copies. "Odyssey Number Five" was their fourth album and was released in 2000. It is their most famous album; it was sold overseas in the United States and Canada. Powderfinger's next two albums were not as popular as the earlier ones, but still got to number one on the Australian Recording Industry Association (ARIA) charts.
Powderfinger started in Brisbane, Australia, in 1989. Ian Haug, John Collins, and Steven Bishop (drums), had been playing music with other bands, when they decided to form Powderfinger. The band's name came from the song "Powderfinger" by Neil Young. Haug met Bernard Fanning at university and Fanning decided to join the band. Later, Jon Coghill joined when Bishop left. Darren Middleton was the last person to join, when Powderfinger saw one of his other bands playing and invited him to join.
Powderfinger released their first extended play (EP), called "Powderfinger", in 1992. This was followed by "Transfusion" in 1993. "Transfusion" was popular in Australia, and got to number one on the ARIA Alternative Chart, a chart for alternative rock music. Powderfinger signed a contract with record label Polydor after releasing "Transfusion".
Their first EPs did not sell badly, so they made an album, "Parables for Wooden Ears", in 1994. It did not do very well, and Fanning said in an interview in 2004 that "the music wasn't very good". The band then released "Double Allergic" in 1996. This album became very popular in Australia; it sold more than 200,000 copies. Jonathan Lewis from Allmusic said ""Double Allergic" established Powderfinger as one of the most exciting Australian rock acts of the late 1990s". When they were making "Double Allergic", Middleton said it was the best music the band had made so far. After releasing the album, Powderfinger went on a tour with You Am I, playing at the Livid concerts.
After "Double Allergic", Powderfinger began to work on their third album. The band worked in Melbourne with a new producer, Nick DiDia. In 1998, they released "Internationalist". The album went to number one on the ARIA Albums Chart, and stayed in the top 50 for 101 weeks. It sold more than 350,000 copies. "Internationalist" was the first Powderfinger album to win an ARIA Award; it won "Album of the Year", "Best Rock Album" and "Best Cover Art" at the 1999 ARIA Awards. "The Day You Come", the first single, won "Single of the Year" in 1999.
On "Internationalist", Powderfinger included songs about their political opinions and social ideas, but they said this was not done on purpose. "Internationalist" sounded different to the band's first two albums. This was because the band experimented with new ways of playing their music and writing songs.
Powderfinger's next album, "Odyssey Number Five" (released in 2000), is their most famous. It won many awards including "Album of the Year" from "Rolling Stone" magazine, and the 2001 "Album of the Year" ARIA Award. It also got to number one on the ARIA Albums Chart. From "Odyssey Number Five", Powderfinger released their most popular single, "My Happiness". It won the 2001 "Single of the Year" ARIA Award, and got to number four on the ARIA Singles Chart. Two songs on "Odyssey Number Five" appeared in movies; "These Days" was from the movie "Two Hands", and "My Kind of Scene" was part of "".