Source of electronics

  • #1
332
1

Main Question or Discussion Point

I have just read the following line:
A vacuum tube was a glass device which used filaments as a source of electronics and could control and amplify electronic signals.

Please remember that I'm not a student of science or math, so please keep your reply simple as much as possible.

What does the "source of electronics" mean?

Are 'electronics devices' those devices which use semi-conductor devices - such as those ones made from silicon? What would you call those devices which don't use these semi-conductor devices, electrical devices? What would you call a hybrid?

Please help me. Thanks.
 

Answers and Replies

  • #2
247
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jackson6612,

my you are full of questions today! :-) Electronic Devices differ from Electrical Devices because Electronic Devices have "Active" components. Examples of "Active Components" are: Vacuum tubes, Diodes, Transistors, FETs etc. Examples of "Passive Components" are: Resistors, Capacitors and Inductors. An incandescent light bulb is an electrical device comprised of a tungsten electrode placed in a vacuum and protected by glass. It exhibits primarily resistance with some inductance and a tiny bit of capacitance. A CFL light bulb is an electronic device that rectifies the line voltage using active components to create an electrical signal discharged through the gas in the light tube. It is certainly possible to light a fluorescent lamp using passive components; however, it is not practical to do so in a package that is convenient and efficient.

Think of "Active Components" as "Non-Linear" devices; that is devices where the output does not vary directly with input. For instance, to amplify an AC signal from +/- 1V to +/- 20V we might use a transformer, but a transformer is a linear device and the amount of Power (Volts x Amps) even in an ideal transformer will remain unchanged (1Vpp @ 100mA on the primary side of the transformer cannot exceed 20Vpp @ 5mA on the secondary side). If we use the same 1Vpp signal and apply it to the input of a Class AB amplifier (regardless if it is constructed from Vacuum tubes, Transistors, FETs, or IGBTs) the signal can be amplified to 20Vpp @ 100A if our amplifier is designed for it, but the electronic device requires an additional input, a "power supply". The Class AB amplifier uses power from the "power supply" to make a "larger copy" of the input signal using "Active Components".

Fish
 
  • #3
4,662
5
The [hot] filament is a source of electrons. Electrons are the smallest and most ubiquitous negative charges we know.

Until the late 1950's when transistors became available, vacuum tubes were used for amplifying electronic signals.

Bob S
 
  • #4
AlephZero
Science Advisor
Homework Helper
6,994
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It is a typo for "source of electrons".

If your next question is "what is an electron", Google is your friend :smile:
 

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