Class of accuracy in electrical measurements and voltmeters have a high but not infinite internal impedance. Thus the measured parameters are somewhat altered during the measurements. Let E be the EMF of the source R be the resistance of the load and r be the resistance of the ammeter. The current through the load is I When the ammeter is connected in series with the load the current I is The difference introduced by the measuring device is then, The ratio of the difference to the actual value is Class of accuracy in electrical measurements In electrical engineering class of accuracy is a figure which represents
Electrical length for whip antennas on portable devices such as walkie-talkies to allow antennas much shorter than the standard quarter-wavelength to be used. The most widely used example is the rubber ducky antenna. The electrical lengthening reduces the bandwidth of the antenna if other phase control measures are not undertaken. An electrically extended aerial is less efficient than the equivalent, full-length antenna. There are two possibilities for the realisation of the electric lengthening. Often both measures are combined. The coils switched in series must sometimes be placed in the middle of the aerial construction. The cabin installed at a height of 150-metres