Memory

(Simplified) functionality

Tubes are electronic components that consist of an evacuated or gas- filled bulb and glass, steel or ceramic. Furthermore they include at least one heated cathode and an anode, by what they are able to constitute electrical signals and mould them different.

By heating the cathode generates an electric field, which releases electrons. Exactly this electric field entails the emission of negatively charged electrons at the hot cathode and the acceleration to the positively charged anode,(in the figure therefore the electrons move from bottom to top), whereby the function of the electron tube is made possible – the resulting voltage, called the anode voltage, is between 200-300 volts.

Later tubes were replaced by semiconductors, such as the diode or even later by the transistor.Reason for this is a long list of disadvantages:

• Sensitivity to vibrations
• Delayed readiness
• High overall heat
• Short lifetime
• High place
• Expensive, especially in comparison with transistors nowadays
• Characteristic curves change gradually, just to name a few...