#### ElectroJake

Joined Sep 27, 2019
11
You are making 2 errors as far as I can see. My previous post, which you seem to have ignored, pointed out the first one.

BTW, I get 4.12V when I do the calculation.

Bob
I'm sorry. I wasn't ignoring your post. I just thought your post was delayed as I thought you were referring to what WBahn had posted:

Which I attempted to use in my recalculations:

Please explain the two mistakes that you see. Thanks.

#### BobTPH

Joined Jun 5, 2013
6,305
Okay, that is the correct formula. What did you get for Ve?

Bob

#### ElectroJake

Joined Sep 27, 2019
11
Okay, that is the correct formula. What did you get for Ve?

Bob
My current calculations are in post #18.

#### Jony130

Joined Feb 17, 2009
5,439
Why do you think that the Vcc is equal to +20V?

#### ElectroJake

Joined Sep 27, 2019
11
Why do you think that the Vcc is equal to +20V?
For that value I wasn't using WBahn's diagram. I just have Vcc as the voltage across the whole right side.

#### LvW

Joined Jun 13, 2013
1,622
ElectroJake....did you read my contribution in post#4?
Just as an exercise for you:
Are you able to find the base voltage (referenced to -10V) under the assumption that there is no base curent IB into the transistor? THIS is a good starting point. And - have you a good and realistic guess for the base-emitter voltage VBE? If yes, you also know the emitter voltage VE and you can use Ohms law for finding the emitter current.

#### Picbuster

Joined Dec 2, 2013
1,041
For that value I wasn't using WBahn's diagram. I just have Vcc as the voltage across the whole right side.
Are you using internet?
There is a lot about transistor stuff.
But you should start with what is a transistor how does it work. Current flow, amplification and it's behave in a circuit.
It's simple but you should remove the unwanted information like the two voltages ( +10V and -10V) hence your circuit is facing 20V.
Regardless of a central zero this has no effect on the currents flowing in your circuit.
If you find X Volt over The emitter resistor then it's X volt over the that resistor regardless the connected + and - 10V.

It is handy draw all the currents in the resistors and transistor legs and name them.
Next step is to produce the formulae for each current and or voltage.
Do not use values keep it to the dimensions.
The trick: working out your formulae should produce a dimension like current, voltage or factor.
If you where looking for a factor and the answer has a dimension( like Volt/ current m/s whatever) the formulae is wrong.
Eq a factor could be current / current r/r V/V
But wen you end up with voltage / current is no factor but resistance so formulae in error.

Picbuster

#### MrAl

Joined Jun 17, 2014
9,780
Hi,

So i guess you are allowed to handle the transistor as a current controlled current source?
Sometimes you are, sometimes you arent.

#### LvW

Joined Jun 13, 2013
1,622
Hi,

So i guess you are allowed to handle the transistor as a current controlled current source?
Sometimes you are, sometimes you arent.
MrAl - I agree to the second sentence.
Normally, each reader of this sentence (in particular, all newcomers) should immediately ask:
What does this mean....."sometimes" ?
This would open an interesting discussion about engineering principles and rules.

#### MrAl

Joined Jun 17, 2014
9,780
MrAl - I agree to the second sentence.
Normally, each reader of this sentence (in particular, all newcomers) should immediately ask:
What does this mean....."sometimes" ?
This would open an interesting discussion about engineering principles and rules.
Hi,

Yeah it depends on the context of the problem.

#### Xavier Pacheco Paulino

Joined Oct 21, 2015
728
Are you familiar with Thevenin and superposition theorems? They are helpful in these types of circuits.

#### BobTPH

Joined Jun 5, 2013
6,305
He knows how to solve the problem. What is causing the wrong answers is sloppiness about signs (+ or -) and using inconsistent references for voltages.

Bob