LITTERATURE REVIEW

French Physicist Alexander Edmond Becquerel first discovered the means of measuring voltage easily in year 1839. It was not fully known until 1888 when Lord Kelvin produced the first voltmeter. According to Prof.Fa Linemen (1932).

Voltmeter is an instrument that measure voltage in either direct or alternating current on scale usually graduated in volts, millivolts (0.001 volts) or kilo volt. (100volt), the typical commercial or laboratory standard voltmeter in use today is likely employed on electro chemical mechanism in current flowing through turns of wire is translated into a reading voltage. This concept is analogue voltmeter whereby pointer is put for deflection whereas in this situation a computer interface is used to display on the screen of the computer system either graphical on numerical.

However, so many inverters has really worked on the voltmeter practically all electros tic voltmeters can found on the types developed by lord Kelvin, the voltmeters was first produced in 1888 and later modeless were able to measure voltages up to about 20,000 volts. This type of volts. This type of voltmeter was in use for laboratory of industrial measurement as late as 1922.the instrument can provide reading in analogue form by moving a pointer that indicates voltage on scale, modern digital voltmeter gives readings numerical displays it does not employ the use of pointer to display the voltage flowing through the turns of wire and also provides output that can be translated over distance can feed into computer digital voltmeter generally have a higher order of accuracy than the analogue instrument.

More so, many types of voltmeters existed before the latest which is computer controlled, they includes. Kelvin vertical electrostatic voltmeter made by Kelvin ProHomley and Baird Glasgow and London, on 1920, Housed in rectangular brass as painted with any colour (usually black) with glass front rigidly fixed to wooden base with 3 leveling screws. Aluminum pointer includes 3 weights 28, 84,333. They come with mahogany carry case with brace fitting “manufacturers instructions for use of vertical electrostic voltmeter” pines to inside of door 3 range 2500v, 6000v, 1200v, multicellar type electrostatic voltmeter i.e. movement is in the plane of attached conductor probably used to measure voltages for train/trains has the useful property that large surges of power through it will not harm it unlike a galvanometer based voltmeter.

Another known inventor, is based in Cambridge, England G 1932, Joseph his who invented Thermonic voltmeter. A very early from a vacuum tube voltmeter which uses 6 volts supply and a triode value. The voltage to be measured is applied to the grid of the valve and when the circuit is balanced the net current is sensitive to this voltage. The current is measured using a Cambridge “UN1P1VOT” galvanometer. This instrument allows measurement of voltages in the range 0.5-1.5 volts only which are displayed on the scale which is linear between voltages.

Also, lindemann Electrometer made in Cambridge England ca 1932. A voltmeter of electrostatic type. The deflection of a minute value is observed through a microscope. Cylindrical brass case with for bass terminals windows on top and bottom (removable for “spare”) showing suspended needle mounted on a black box with four cross connected plates. Mounted on a black box with hole covered in frosted glass in wall leading to a prison directing light through the bottom window. A swiveling microscope with scale is also mounted viewing the needle. Designed by prof. F A handymen force use in astronomical work. Operation is similar to mat of quadrant voltmeter. It has a high sensitivity and stable zero and does not require leveling. The middle is attached to torsion fibre which is fixed under tension to fix the centre rotation. The voltage across the plates induces a free on the needle which is equiubium is balanced by a restoring force from the five since no minor is needed, moving parts only have a small inertia, therefore keeping the period low. An earth terminal eliminates problems with stray capacitance.