IDENTIFYING DIODE LEADS
When the diode is to be connected in a circuit, there must be some means of identifying the anode and the cathode. Diodes are made in different case styles so there are different methods of identifying the leads. Large stud-mounted diodes often have the diode symbol printed on the case to show proper lead identification. Small plastic case diodes often have a line or band around one end of the case, Figure 50–8. This line or band represents the line in front of the arrow on the schematic symbol of the diode. An ohmmeter can always be used to deter- mine the proper lead identification if the polarity of the ohmmeter leads is known. The positive lead of the ohmmeter must be connected to the anode to make the diode forward biased. A junction diode is shown in Figure 50–9.