Regulator

[anatech]

Hi Stocker,
I was thinking the same way. I was going to wait for a picture or diagram to show what was going on.

I wouldn't call a resistor reference a regulator at all.

-Chris

[argonrepublic]

I am so thankful for the help on this site. You guys probably love a challenge and would like to reverse engineer it. I don't have a camera here. I couldn't draw it because I need practice focussing. I get distracted easily and when I look at this PCB, my eyes go in to many directions. I am going to try one more time to get schematic. I would rather save your patience for other upcoming projects. I am a beginner and need alot of help. I will be back soon
Thanks

[anatech]

Know anyone with a camera phone?

"The Source" had $30 digital camera's last year. They might be enough (480 X 640, fixed focus).

-Chris

[Stocker]

Originally posted by anatech
Hi Stocker,
I was thinking the same way. I was going to wait for a picture or diagram to show what was going on.

I wouldn't call a resistor reference a regulator at all.

-Chris

We are on the same page. Note that I didn't mention regulation at all in that post...





-David

edit:/ oh yes, if you are having trouble focusing to do even this, you will have a very hard row to hoe when working DIY electronics.

[argonrepublic]

The focus will come. I took a 6 month break from everything. I can't believe the way my head feels after working in the studio or on repairs. I feel like my brain has been doing pushups. I have only been using my brain for about two weeks now. It's pretty mushy. On the power supply topic...
I have two rackmount power supplies. One is a behringer Mixer Power supply(transformer, caps, resistors and regulator) The Other is a very complex looking setup(Kyocera) Stuck in a Dynamix rackmount case made to look like it goes with my mixer. I am not sure which one to use. The Behringer puts out 48V Phantom, 12Vdc aux, 5Vdc aux and +/-17Vdc. It is very versatile but I wonder about the quality. When using my mixer, I get a faint hiss during silence. I wondered if that was coming from PSU.
Back to the regulator.
In my synth I have some ICs that require +/-7.5 Volts. My kyocera has a +/-5vdc output. Would I have a better chance of testing ICs with +/-5volts than the present +5Vdc/-11vdc? What effect does difference on positive and negative rails have on IC function.
Thanks

[Stocker]

Any effect, ranging from no power-on to explosion and anywhere inbetween.

Hiss from a mixer is in the mixer itself, most likely.

You can add another regulator stage to take the +/-17V to the lower voltage you need.

On a side note, regulated power supplies are pretty simple to put together and they can be pretty cheap with careful component sourcing.

[anatech]

Hi Stocker,
Can't disagree with anything you've said yet.

-Chris

[davidsrsb]

Originally posted by AndrewT
I think there is no feedback in this circuit so it follows there can be no oscillation.

Emitter followers with capacitors on the emitter are prone to rf oscillation, especially if you add capacitance from the base to ground.

You could also add a reverse polarised diode from collector to emitter to prevent reverse breakdown if the input is shorted while the output capacitors are charged

[AndrewT]

Hi David,
and I thought these followers were immune to the problem. So much for my tutors.

[jan.didden]

Originally posted by AndrewT
Hi David,
and I thought these followers were immune to the problem. So much for my tutors.

An emitter follower's output impedance rises with frequency. That makes it look like an inductor. Just add some caps and presto! oscillations ..

Jan Didden