What is a transistor?

Hey guys,

I am having problems understanding what is a transistor. When I do a search it shows me that its made of semi-conductor material and stuff, I don't want to know that. I want to know what is does as in a battery supplies power, resistor limits current etc. I would really like it if someone could give me a basic explanation of what is a transistor. Thanks in advance :).

-Prickly Potato

sort by: active | newest | oldest
Kiteman2 years ago

It's a switch with no moving parts.

Simply, a current is "trying" to flow between the collector and emitter terminals, and when a voltage is sent to the base terminal the switch "closes" and the current flows.

The current triggering the base is typically much smaller than the current being controlled.

Don't want to be picky but normal transistors are current driven rather than voltage activated.

for more detail read my instructable posted below.

Slightly pickier...The BJT is current driven, the FET is voltage driven....

Pick away - it's what I get for posting tired.

The Prickly Potato (author)  Kiteman2 years ago

Can you describe what you mean by base terminal


seandogue2 years ago

A standard bipolar junction transistor is not a switch, as some might have you believe. Instead it is far more accurately described as a current-controlled valve, since it can be used as a switch OR as an amplifier.

In a similar way, a FET (field effect transistor) can be more accurately described as a voltage-controlled valve, again, since it can be used as both a switch or an amplfier.


Just goes to show you what a popularity contest this site has become. What a joke. Kiteman had it completely wrong.

rickharris2 years ago

Gotta read more then the first paragraph or 2 of an article if you want to learn about something. ;)