Atp Emtp Rule Book Ebook 13
Christal Rasband
where d is the distance between the two electrodes. When the external charge moves between the electrodes, the induced charge on each electrode varies, but the sum of induced charges remains always equal to the external charge q = q1 + q2. If two electrodes are connected to form a closed circuit, the changes in the amount of induced charges on the electrodes lead to a measurable current between the electrodes. As it is illustrated in Figure 1.2, when the external charge is initially close to the upper electrode, most of the field strength will terminate there and the induced charge will be correspondingly higher, but as the charge moves toward the lower electrode, the charge induced on the lower electrode increases. This means that the polarity of outgoing charges from electrodes or the observed pulses are opposite. In general, the polarity of the induced current depends on the polarity of the moving charge and also the direction of its movement in respect to the electrode. As a rule, one can remember that a positive charge moving toward an electrode generates an induced positive signal; if it moves away, the signal is negative and similarly for negative charge with opposite signs. In a radiation detector, a radiation interaction produces free charge carriers of both negative and positive signs. The motion of positive and negative charge carriers toward their respective electrodes increases their surface charges, the cathode toward more negative and the anode toward more positive, but by moving the charge away from the other electrode, the charge of opposite polarity is induced on that electrode. The total induced charge on each electrode is due to the contributions from both types of charge carriers, which are added together due to the opposite direction and opposite sign of the charges.