SSLV1.1 builds & fairy tales

[stajo]

So I should go higher on both fixed and trim? 40% less is 2,5ish. 3900 and 1K?

 

[Salas]

Yes try one section with those values first to see.

 

[stajo]

Testing a positive reg that I built for some reason that I dont remember. I had it on the bench and played with it. It has a 5R6 current resistor and a 180 fixed and 4K trim, so wide dial in. Runs super stable at 12 volt out from a dc lab reg. It has rectifiers but they just drop voltage now. Probes in my hand is on the filter C. It has a light dummy load of 270 for test. Could use it for miniDSP maybe or something.

 

[Salas]

Its a useful module. What is the Vdrop across its 5R6? 2.73V maybe?

 

[stajo]

Cranked the load up to a staggering 48 ohms / 250 mA. No sweat. Here you see that.

 

[stajo]

Yes I guess I built is as a test and to use for 5 or 12 v use on the bench if needing quality juice. Its been running close to an hour now. It dropped 10 millivolt after a minute, after that it has been declaring 12,01 flat. Heatsink is cool/luke. Cool stuff.

I notice I have a zobel with a lyt on output. Probably didnt read up, just smacked in the comps. Maybe switch caps or bridge the 1 ohm.

Vdrop is 2,74 now

 

[Salas]

If the 5.6R has precision value then the CCS runs 0.47A but the bench PSU measures 0.49A. Or its a bit smaller R.
Regarding output termination seems not bothered by the extra "ESR" from the resistor. Because so stable already.
The better modern electrolytics can have very low ESR sometimes so 1 Ohm extra does not upset the system at all.

 

[stajo]

The bench psu might not report current that accurate. Testing leds on 3 mA said 1 mA on the psu. Its a 1% thickfilm.

 

[Salas]

Most possibly the 100 Euro class bench psu miss-reads current. I am suspecting you will characterize this bench psu for tolerance with few light to heavy ranging loads and a DMM in series some lazy day. But use the 10A socket only not to break an expensive mA mode DMM fuse.

 

[stajo]

I dunno why it showed those figures before but now it looks decent accurate.

 

[Salas]

Maybe 50Hz noise on the probes and leads by touching. Can throw its reading off a little.

 

[stajo]

Or 50 Hz shaky hands 🙂

It runs stable like a freight train in the night. Tomorrow some css leds matching etc

 

[stajo]

How workable is it really with a fixed tx to use it as a 5-12 volt bench supply?

Must be a really strong k117 here

 

[Salas]

It is workable since it got a large sink that can take the excess vin-vout created dissipation when set as low out. By Vdrop / Ω on the fixed resistor you can determine the in situ idss of that Vref Jfet.

 

[Salas]

Or 50 Hz shaky hands 🙂

In #4,605 there is much more AC component indication on the secondary screen of the big Brymen vs #4,610. So there was some interference indeed.

 

[stajo]

3,42 in circuit so like 4,8 with Toshibas model

 

[Salas]

There's only one transistor Vbe where that Jfet nests in so it always gives lower than full idss. Fortunately it sees say 0.6V Vbe like 1-1.2V Vds diff because Vgs is negative and Vbe is positive. Gets it barely on top of ohmic region curve for a K117GR. Kinda of a timid CCS. A Triodized Jfet if you like. 🙂

 

[Salas]

The SSLV supplies include a ton of odd circuit culture so they inevitably sound different than most other regs. You love them or you skip them but their individuality is a real thing.

 

[stajo]

We will see. Right now its just some opamps that shall have decent juice, but as usual when I start something I get nerdy.

Finally, deep dig! Found a lost pair that was supposed to enter an application but never did. Must investigate.

 

[Salas]

After a dust off a test. What uF/brand/type are the output lytics?