Get On Board with. Compass Card. Compass Card is the smart card and smart choice for transit passes in the San Diego region. Compass Card is your ticket for the Bus, TROLLEY, COASTER, and SPRINTER.ompass Card. Compass Card is the smart card and smart choice for transit passes in the San Diego region. Compass Card is your ticket for the Bus, TROLLEY, COASTER, and SPRINTER.
Use of Vacuum Tube Diodes Gradually p-n junction semiconductor has come in the market and vacuum tubes got replaced by them. The most basic structure of vacuum tube is vacuum diode. Still today somewhere vacuum tubes are being used widely. These fields for application of the vacuum tubes are in Atomic Clocks; Audio Systems; Car Dashboards
Operation of Zener Diode: 1  Zener diodes are normally used only in the reverse bias direction. 2  It means that the anode must be connected to the negative side of the voltage source and the cathode must be connected to the positive side. Varying amount of reverse current can pass through the diode without damaging it. 2  The breakdown voltage or zener voltage (VZ) across the diode remains relatively constant. 3  The maximum reverse current is limited, however, by the wattage rating of the diode.