Peltier Sentence Examples
As a lawyer his greatest public efforts were his lectures (1799) at Lincoln's Inn on the law of nature and nations, of which the introductory discourse was published, and his eloquent defence (1803) of Jean Gabriel Peltier, a French refugee, tried at the instance of the French government for a libel against the first consul.
When a current is passed through a solid alloy, a series of Peltier effects, proportional to the current, are set up between the particles of the different metals, and these create an opposing electromotive force which is indistinguishable experimentally from a resistance.
When the Revolution developed the importance of the press, Rivarol at once took up arms on the Royalist side, and wrote in the Journal politique of Antoine Sabatier de Castres (1742-1817) and the Actes des Apdtres of Jean Gabriel Peltier (1770-1825).
Peltier (1785-1845) in 1814 discovered that a current passed across the junction of two metals either generated or absorbed heat.
Peltier (1834) that heat is absorbed at the junction of two metals by passing a current through it in the same direction as the current produced by heating it, was recognized by Joule as affording a clue to the source of the energy of the current by the application of the principles of thermodynamics.Advertisement
The order of the metals in respect of the Peltier effect was found to be the same as the thermoelectric series.
But on account of the difficulty of the measurements involved, the verification of the accurate relation between the Peltier effect and thermoelectric power was left to more recent times.
The coefficients, P and P', are called coefficients of the Peltier effect, and may be stated in calories or joules per ampere-second.
The Peltier coefficient may also be expressed in volts or microvolts, and may be regarded as the measure of an E.M.F.
Clausius (1853) that the Peltier effect varied directly as the absolute temperature, and that the E.M.F.Advertisement
Like the Peltier coefficient, it may be measured in joules or calories per ampere-second per degree, or more conveniently and simply in microvolts per degree.
Consider an elementary couple of two metals A and B for which s has the values s and s" respectively, with junctions at the temperature T and T+dT (absolute), at which the coefficients of the Peltier effect are P and P+dP. Equating the quantity of heat absorbed to the quantity of electrical energy generated, we have by the first law of thermodynamics the relation dE/dT =dP/dT+(s' - s").
The signs of the Peltier and Thomson effects will be the same as the signs of the coefficients given in Table I., if we suppose the metal s to be lead, and assume that the value of s may be taken as zero at all temperatures.
The Peltier effect was only a small fraction of the total effect, but could be separated from the Joule effect owing to the reversal of the current.
According to this formula, the Peltier effect is a linear function of the temperature.Advertisement
The flow of the current will produce a fall of potential ER'/R in the lead from cold to hot, and ER"/R in the iron from hot to cold, but the potential difference due to the Peltier effect at either junction will not be affected.
The Peltier effect and the thermo-E.M.F., on the other hand, do not depend on the state of the surfaces, but only on the state of the substance.
It is equally evident that chemical affinity between the metals cannot be the explanation of the Peltier E.M.F.
Although it is possible that differences of potential larger than the Peltier effect might exist between two metals in contact on open circuit, it is certain that the only effective E.M.F.
But the reason for concluding that there is no other effective source of potential difference at the junction besides the Peltier effect, is simply that no other appreciable action takes place at the junction when a current passes except the Peltier generation or absorption of heat.Advertisement
In this case, however, in order to account for the phenomenon of the Peltier effect at the junctions, it is necessary to suppose that there is a real convection of heat by an electric current, and that the coefficient P or pT is the difference of the quantities of heat carried by unit quantity of electricity in the two metals.
The Peltier effect, on the other hand, may be ascribed entirely to convection.
If, therefore, we are prepared to admit that an electric current can carry heat, the existence of the Peltier effect is no proof that a corresponding E.M.F.
In order to explain the Peltier effect, Kohlrausch further assumes that an electric current, C, carries a heatflow, Q= ABC, with it, where " A is a constant which can be made equal to unity by a proper choice of units."
If A and Bare constant, the Peltier effects at the hot and cold junctions are equal and opposite, and may therefore be neglected.Advertisement
His great experimental discovery, known as the "Peltier effect," was that if a current pass from an external source through a circuit of two metals it cools the junction through which it passes in the same direction as the thermo-electric current which would be caused by directly heating that junction, while it heats the other junction (see Thermo-Electricity), Peltier died in Paris on the 27th of October 1845.
The range of Steele's observations was too small to show any certain deviation from the formula, but he notes capricious changes attributed to change of condition of the proved to be proportional to the square of the current, the Peltier effect is reversible with the current, and being directly proportional to the first power of the current, changes sign when the current is reversed.
Semi conductor thermoelectric device which works on the Peltier effect.
Explain what is meant by the Peltier coefficient and thermoelectric power.
Thermoelectric cooling is also known as the Peltier effect.
Most tabletop chillers that utilize the Peltier effect both heat and cool.