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
In the amplifier circuitry, diodes may be used to provide a known (approximately) voltage drop where required by the design of the circuit. They can also be used for temperature feedback, although for direct temperature compensation a transistor is more common. These diodes are generally small-signal types like 1N4148. In logic switching, diodes are often used for simple OR-type functions. Look on Wikipedia for diode OR. These are small-signal types. If the amplifier has a switching power supply, or is a Class D amplifier, high speed switching diodes are used extensively.