few questions

[Victor Frankenstein]

Whats is a comparatror ?

What is a multivibrator ?

Why do they have two kinds of bi-polar transistors ?

 

[D.J.]

Victor Frankenstein,

We have two kinds of bipolor transistors ( NPN and PNP ) becuase of the different layers of silicone.

In an NPN transistor, the inside consists of two types of silicone, P-type and N-type. The assimbly is NPN.

In an PNP transistor, the inside consists of two types of silicone, P-type and N-type. The assimble is PNP.

Does this explain it good enough? I can tell more if you want.

D.J.

 

[bonxer]

A comparator, as the name suggests, is a device which compares things. It compares voltage levels. On one pin, you connect your reference voltage. The other pin is the test voltage. The output of the chip changes whenever the test voltage is equal to or greater than the reference.

A multivibrator creates an alternating signal, like a 555 timer that generates a square wave pulse. It goes high, low, high, low, high, low... etc and keeps generating that same signal over and over, you just use resistors and a capacitor to determine the frequency that it switches signals.

There are manybi-polar transistors, high gain, high power, switching, but you probably mean why are there NPN and PNP transistors. I suppose the most basic thing would be that if you give a PNP a low input to the base it will source voltage. On the other hand if you give an NPN a high signal, it will provide a sink/ground. You can connect them in ways such that if you give each a common signal which is high, the PNP will turn on and source while the NPN is off. Then if you take the signal low, the PNP turns off, while the NPN will sink.

 

[lord loh.]

What is a multivibrator ?

Multivibrator is a circuit with two quasi satble states(unstable states). It keeps switching between these states without any need for an external triggering.


A comparator gives a zero output when it's two inputs are the same. else it is either +ve or -ve. It is a differential amplifier.

 

[Dean Huster]

We have two kinds of bipolor transistors ( NPN and PNP ) becuase of the different layers of silicone.

D.J., Silicon Valley is found in the Santa Clara CA region; Silicone Valley is otherwise known as Hollywood CA.

Dean

 

[audioguru]

Hey Dean,
He, he, he, he! :lol: :lol:
Silicone Valley! :lol: :lol: :lol: Silicone Valley! :lol: :lol: :lol: Silicone Valley! :lol: :lol: :lol: Silicone Valley! :lol: :lol: :lol:

 

[Roff]

Lord Loh, Bonxer, there are three types of multivibrators.

 

[D.J.]

Dean Huster,

Ok, I did not get that one. :?

D.J.

 

[lord loh.]

Lord Loh, Bonxer, there are three types of multivibrators.

Oh... Got confused... Yes..Ther is an astable multivibrator(two quasi stable states), monostable (1 quasi stable state) and bistable(2 stable states)

The wikipedia article is a good link....

 

[audioguru]

Hollywood (Silicone Valley) also has the same three types of people. He, he. :lol:

 

[Roff]

Dean Huster,

Ok, I did not get that one. :?

D.J.

Silicone makes lousy transistors. Silicon makes lousy glue (or breast implants).

 

[audioguru]

My silicone caulking sticks very well to things, I am having trouble lately with 2-parts epoxy cement: it never seems to cure. :lol:

EDIT: OOps, I also got silicon and silicone mixed-up!

 

[Styx]

Sod silicon, the Japanese have managed to N-dope Diamond (they have already P-typed doped for a while)

SO now they have managed to make a PN diode as oppose to a schokky.
So next a Thyristor, then a BJT, then a FET, then a IGBT!!!!

WooHoo

And as to Silicone, Saline gives a more natural feel

 

[D.J.]

ok :?