a question about transistors

[fritz]

http://books.google.at/books?id=bkOMDgwFA28C&printsec=frontcover&dq=the+art+of+electronics&source=bl&ots=F2hoQCa4Yo&sig=h1FliBkfus0oM16iDBw9GCGE_ds&hl=de&ei=esRuTffRC4bGtAbwgt3dAQ&sa=X&oi=book_result&ct=result&resnum=8&ved=0CGEQ6AEwBw#v=onepage&q&f=false

In this book you can find driver stages, and lots of other information which may help.

[Bizzy]

This is very infomrative and helpfull.
Basically I want to use a transistor to control a pulse motor. Turning on and off at certain intervals. So it sounds like a Mosfet would suit my needs better.
Bizzy

[FatBird]

In actuality, NPN & PNP Xistors can be turned on by MicroVolts.

For proof, look at a Transistor Radio.  The voltage on the antenna that feeds the First Stage, is typically Microvolts.


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[neptune]

@ Fatbird . What you say is only partly true , and is likely to confuse a novice .
Microvolts from the antenna are fed into a high Q tuned circuit , to magnify the voltage . Also base bias resistors are used to "partly turn on " the transistor already , so that a small signal voltage will turn on the transistor a further amount . That is how signal amplification works .

[Bizzy]

@ Fatbird . What you say is only partly true , and is likely to confuse a novice .Microvolts from the antenna are fed into a high Q tuned circuit , to magnify the voltage . Also base bias resistors are used to "partly turn on " the transistor already , so that a small signal voltage will turn on the transistor a further amount . That is how signal amplification works .

Yes I am confused enough...

So is that the reason why you put a resistor at the base of a transistor in a joule theif?
Bizzy