Category Physics

Why was the introduction of the fuel cell a milestone?

        Fuel cells are devices that generate electric current through chemical reactions. To put it better, a fuel cell uses chemical energy of hydrogen (or another fuel) to produce electricity in a clean and efficient manner. Its only products are electricity, heat, and water, and hence it is clean.

            There are a wide range of applications for which fuel cells can be used. This includes transportation, emergency power back up, material handling etc. compared to other technologies, fuel cells have many advantages. They are more efficient, and have lower emissions. That is, they do not emit dangerous substances like carbon dioxide or air pollutants, as their only products are water and heat. Yet another advantage is that fuel cells operate in a silent manner.

            The history of fuel cells began with the Welsh physicist Sir William Grove. In 1839, he demonstrated the first crude fuel cells. Although many people have tried to work on the concept of converting chemical energy into electric power, most of them were unsuccessful due to lack of resources.

            The first successful fuel cell was developed by the British engineer Francis Bacon in 1932, using hydrogen, oxygen, an alkaline electrolyte and nickel electrodes.

 

Why is it said that the amplifier and triode changed the history of electricity?

          An electronic amplifier is a tool that can amplify or increase the power, current, or voltage of a signal. It could be either a separate piece of equipment, or an electrical circuit within another device, but in general, amplifiers are used in almost all electronic equipment that we see around. They are particularly used in wireless communications and broadcasting.

          Before the amplifiers were introduced, mechanically coupled microphones were used to serve the purpose in telephone repeaters.

          In 1906, the triode was invented. It was the first electronic device that could amplify signals. It is a fundamental form of vacuum tube developed by the American inventor Lee De Forest. He had only a little understanding of how the tube worked.

          However, the discovery revolutionized electrical technology, and laid the foundation of electronics. It also made possible radio broadcasting, talking motion pictures, and countless other applications.

 

Why is an ammeter important?

         An ammeter is an instrument used to measure the flow of electric current in a circuit. It measures current in terms of amperes, which is the unit of current. The speed and force of a current can be measured using this instrument.

         In the past, the instrument relied on the Earth’s magnetic field to take the readings of current. But as technology improved, better ammeters were designed and developed. Ammeters are mostly used in science laboratories. Other than scientists, electricians also use this instrument, to check the electric circuit.

        There are smaller units of reading to amperes, namely, milliamperes and microamperes. These are measured using milliammeters and microammeters respectively.

        There are two types of ammeters – analogue and digital. In analogue ammeters, there is a needle that points to the reading. In digital ammeters, they are displayed digitally.

 

Why is the voltmeter important equipment?

        A voltmeter is an instrument that measures the voltage between two points in an electric circuit. It can be connected to a circuit by joining its positive and negative wires to where the voltage is. With such an arrangement, the instrument is said to be parallel to the electrical circuit.

       A voltmeter can be used for many purposes. For instance, to check whether there is any more electricity left in a battery.

       In an analogue voltmeter, the pointer indicates the number of volts. In a digital voltmeter, the reading will be displayed digitally. There are also voltmeters that can be mounted on a transformer, and other huge devices.

       Yet another variety is a voltmeter that uses amplifiers in them. Such meters can measure very small, or tiny voltages of microvolts, or even less.

 

What is a galvanometer?

         A galvanometer is a tool that measures the flow of electric charges through a wire. This basic device consists of a coil placed in a magnetic field. It can be used for detecting and comparing small electric currents.

        The ideas of galvanometers are known to have developed from an observation made by Hans Orsted in 1820. He had found out that the needle of a magnetic compass deflects near a wire that has electric current passing through it. But it was Johann Schweigger who built the first sensitive galvanometer in the same year. Galvanometers, since then, came to commercial use.

        A galvanometer can be used as an ammeter, as well as a voltmeter. By connecting a shunt in parallel to the coil, it acts an ammeter, and if the shunt is connected in series with the galvanometer coil, it becomes a voltmeter. 

What is a multimeter?

          A multimeter is an instrument that measures the voltage, current, and resistance of an electrical device. Also known as a VOM (Volt-Ohm-Milliammeter), they are very useful in providing field measurements or detecting faults with accuracy.

          The first multimeter was invented by Donald Macadie, a British post office engineer who was unhappy with the need to carry separate instruments needed for the maintenance of telecommunication circuits. His invention was the instrument that could measure amperes, volts and ohms, and was named the avometer.

          The device is commonly used by electricians and other experts to troubleshoot problems on appliances, motors, circuits, power supplies and wiring systems. They could use the device on batteries, switches, power sources etc for measuring or diagnosing.

            Multimeters can be analogue or digital. Analogue multimeters are cheaper, but their readings are not as accurate as the digital meters. Recent digital multimeters are advanced enough to measure extremely tiny differences or fluctuations.