ELECTRONIC PRINCIPLES - OD1647 - LESSON 1/TASK 2
FIGURE 71. SIZE COMPARISONS OF ELECTRON TUBES AND
solidstate devices may require no more than 20 watts of power.
However, the same number of tubes would require several
kilowatts of power.
For highpower applications, it is a different story; tubes have
the upper hand. The highpower electron tube has no equivalent
in any semiconductor device. This is because a tube can be
designed to operate with over a thousand volts applied to its
plate, whereas the maximum allowable voltage for a transistor is
limited to about 200 volts (usually 50 volts or less). A tube
can also handle thousands of watts of power. The maximum power
output for transistors generally ranges from 30 milliwatts to
slightly over l00 watts.
When it comes to ruggedness and life expectancy, the tube is
still in the competition. Design and functional requirements
usually dictate the choice of devices. However, semiconductor
devices are rugged and longlived. They can be constructed to
withstand impacts that would completely shatter an ordinary
electron tube. Although some specially