SSLV1.1 builds & fairy tales

[Salas]

But if you mean Vout total then its 13.73 with trimmer at zero minus 4V from Leds minus 0.6V Vbe. Roughly.
I.e. say 9.13V on the 2k7 fixed resistor alone makes 3.38mA. More likely.

 

[stajo]

Very strange. The 10 v measured values are in post #4665

 

[Salas]

How much drop you got on the 2k7 alone?

 

[stajo]

This is how I measure total resistance. The trimmer is soldered for easy remounting

 

[Salas]

Correct way to measure total resistance. A voltage drop on the fixed resistor alone will tell us running current in the Vref. Rest of contributions on top of that Vdrop is Leds, one Vbe, trimmer.

 

[stajo]

2K7 (2K691)

3,49 mA

 

[Salas]

Logical, and near where guessed (#4,681). Do you remember the noted 10V test idss of Q203?

 

[Salas]

Black probe on top gives the positive Voltage value? That's a negative section, right?

 

[stajo]

I had to run out for pizza and beer before I catch tourettes.

Q203: as a matter of fact, since this is a photo documentory, I think I do. Very blurry iphone pic, think I have written new value 4,22 under old 4,18

 

[stajo]

Negative yes

 

[Salas]

4.22/3.49=21% loss of Idss under only Vbe for VDS. Good for the location small Vgs allowed less loss which means good more robust CCS than worst case 40% loss.

 

[stajo]

It might have been just a false impression but it felt like the negative reacted more sluggish than the positive. Both on startup and when turning the trim

 

[Salas]

2K7 (2K691)
View attachment 1306818

3,49 mA

No, 9.390V/2691Ω=3.17mA
4.22mA Idss / 3.17mA in situ = 33% loss

 

[Salas]

It might have been just a false impression but it felt like the negative reacted more sluggish than the positive. Both on startup and when turning the trim

C202 or C201 Vref filteing uF must be charged and discharged. So how many mA in Vref vs what value C make the adjust response faster or slower.

 

[stajo]

What calculator are you using?

 

[Salas]

I used the "I pressed the wrong digit" calculator brand

 

[stajo]

You are forgiven my friend. Maybe you didnt have your pizza and beer? I, on the other hand, am strong as an oxe and sharp as a razor after a pizza speziale and two lager if you would like more measurments.

Otherwise lets talk current, R101/201, what do you think we should aim for?

 

[Salas]

Today its meat day. Orthodox Easter.
About R101/R201 just measure vdrop as it is now across each and calculate less R for more mA. Some convenient values.

 

[stajo]

Resistor Parade

Good enough for this geezer. One turn on the 200 ohm 25 turns trimmers are like 5-10 mV. Very exact dial in.

 

[Salas]

Very good outcome! Congratulations 👏