# constant current source with transistor

Nov 27, 2023
28
So I just drew up another circuit, do u guys think this would work?

Its two power supplies, one for the base of the transistor, and one for the collector, and it
shorts away from the load to activate the base.

Its resistance actuated, not voltage.

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• ccsource.png
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#### Delta Prime

Jul 29, 2020
1,969
shorts away from the load to activate the base.

Its resistance actuated, not voltage
You just made a room temperature super conductor and that means no resistance not even voltage can find the current. I'm speaking your language bro!
But now I'm scared...
Boo!
Danger here be dragons..

#### Martaine2005

May 12, 2015
4,952
What is the diagram supposed to be?.
That poor transistor is toasted!.

Nov 27, 2023
28
So I take it you dont like the circuit.

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,728
So I take it you dont like the circuit.
No at all, unfortunately:
- Not recognizable whether the transistor shown should be NPN or PNP.
- Not recognizable what that open circuit with the connectors "+" and "-2 and the label "base" means.

Have a look here at a selection of BJT based current sources.

Nov 27, 2023
28
I had a look at the circuits.

What I would like to see is someone do it without a transistor.

I mean base of the transistor, for base. the + and - are the power entries, med res is the "median resistor" which judges the short away strength.

The cool thing about the circuit is it acts as a short if anything is in series with it.

Nov 27, 2023
28
So I was just stuffing around in falstad again, and what always pissed me off is the capacitors seem to do nothing, all u see is the battery behind the capacitor, u can even delete the capacitor and it doesnt make a difference to the circuit.

So, what I've found just today, is I can get the flavour of capacitors more if I charge them with a low duty cycle oscillator and then u can actually the see the little bastards discharge without the battery just keeping on refilling them constantly and u never even get to see their behaviour at all, being little micro batteries.

The cool thing, that I'm liking, and I might be swapping ships, is that when a cap divides down two pathways the energy actually divides similar to a constant current system, and I actually think that looks alot more useful to me, like I might get an amplifier out of it and more, but I have to bite the bullet and just give up on this oscillator i've been trying to make for a decade now, and It doesnt look good for it.

But If I just go get a couple of transistors and put the oscillator together, I can run this low duty cycle oscillator and get some cool cap dividing happening, and maybe itll have to be a half happy story, instead of being an absolute crashing win for me, which might end up me being depressed anyway so It could be a good thing, to not always get what I want.

So, heres me, giving up on my oscillator, it doesnt work, Im going to get a couple of transistors now, but I'm going to try and keep it to just the oscillator, and do the rest with my crazy passive techniques.

#### Delta Prime

Jul 29, 2020
1,969
and do the rest with my crazy passive techniques.
In no way are they passive!
Don't your parents pay enough attention to you!?

Feb 19, 2021
771
2 part minimum approach :

Regards, Dana.

#### kellys_eye

Jun 25, 2010
6,514
So I was just stuffing around in falstad again,
My bold.

Are we headed in 'that' direction again? The OP seems far too samey-samey as another (now banned) poster who perpetuated the falstad sh*t. Same thought processes too.

"Caution Will Robinson".....

Nov 27, 2023
28
Spice lies alright, confuses the absolute shit out of me, I need to get some more real components and do some real testing as well.

#### AnalogKid

Jun 10, 2015
2,893
, all u see is the battery behind the capacitor, u can even delete the capacitor and it doesnt make a difference to the circuit.

I'm trying to follow along, but it is difficult. Please post a schematic of the oscillator. Be sure to use the correct symbol for each component, and include a reference designator and part value.

ak

#### Delta Prime

Jul 29, 2020
1,969
I need to get some more real components and do some real testing as well

Spice gives you an output depending on the input ,garbage in garbage out. There is a phrase called the ( K.I.S.S) method
Keep .It .Simple .Supid.
I'm thinking the questions you ask are for getting attention. forget spice, if you'd like to use real components you need real test equipment . I always have pencil and paper I offered you before to provide you with test equipment and components but I never offered you assistance... think of something very simple something you consider interesting made of two or three components and a power supply and I will get a piece of paper and pencil and draw a schematic or a couple versions of the idea you have submitted, then we could do the math together,simple math, simple circuit . You seem to have a genuine interest in electronics.Consider my proposal, nothing ventured nothing gained.

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,728
What I would like to see is someone do it without a transistor.
The cool thing about the circuit is it acts as a short if anything is in series with it.
What's coola about that and what has that to do with a current source?

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,728
do the rest with my crazy passive techniques.
crazy - that's today's word

#### Harald Kapp

##### Moderator
Moderator
Nov 17, 2011
13,728
Spice lies alright, confuses the absolute shit out of me,
It's not SPICE that has a problem. It's your lack of understanding that causes you to "design" circuits that make no sense, not to us and definitely not to a simulator.
Your rant in post #7 is a good example.

#### Martaine2005

May 12, 2015
4,952
Sounds TOO similar to ratstar

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