What is the output of this UJT relaxation oscillator circuit?

[Femme_physics]

Oops, sorry! I guess I was so sure I'm right... ;)

http://img513.imageshack.us/img513/5575/vpvpvpvvvvvv.jpg

 

[I like Serena]

Hmmm... no flowers or anything!

190/100

 

[NascentOxygen]

I assume as in before Vout = Vp + Veb ?

Was this established somewhere before? If you mark "voltage arrows" on your schematic, using KVL, you'll be able to demonstrate whether this should be a + or a minus Veb.

You are deciding here how to sketch the Vout pulse, and you need Vout's maximum value in order to sketch it. We know Vp (from Vcc and the manufacturer's data), so what value are you going to use for V_EB in the above equation?

 

[Femme_physics]

Was this established somewhere before? If you mark "voltage arrows" on your schematic, using KVL, you'll be able to demonstrate whether this should be a + or a minus Veb.

You are deciding here how to sketch the Vout pulse, and you need Vout's maximum value in order to sketch it. We know Vp (from Vcc and the manufacturer's data), so what value are you going to use for V_EB in the above equation?

You're right, I confused the signs

http://img825.imageshack.us/img825/336/signsz.jpg

 

[NascentOxygen]

Can you check that last line ...

 

[Femme_physics]

Oh, sorry

Vout = Vp - Veb

 

[Femme_physics]

Confirmation?

 

[NascentOxygen]

Confirmation?

Ah, that's looking better.

Though I'm still wondering what value you'll use for that unijunction transistor's V_EB?

 

[Femme_physics]

We don't know its value so we can't actually solve it, just leave it as an unknown

We can make the assumption it's 0.7 volts of course...but maybe it's best to stay on the safe side and leave it as an unknown?

 

[NascentOxygen]

We don't know its value so we can't actually solve it, just leave it as an unknown

We can make the assumption it's 0.7 volts of course...

If you need a value, it's going to be the value of V_EB when in the breakdown region, viz. V_V. For your problem, V_V is given as 2.1V (or maybe 1.1V depending on which question is considered).