The simplistic Salas low voltage shunt regulator

[merlin el mago]

You got a squeaky clean line with the dummy but I can see some modulation on the first picture. Use two wire mode and JFET instead of R6 to see if it gets any better or its just the logic gate noise propagating on the rail.

How can we wired the JFET: d+g one leg and s the other leg or etc...? wich JFET: sk117, sk170, etc?

 

[jimchan]

nice... thx Salas 🙂

 

[Salas]

How can we wired the JFET: d+g one leg and s the other leg or etc...? wich JFET: sk117, sk170, etc?

replace r6 with 117gr

 

[merlin el mago]

No matter Iss right?

 

[Salas]

2mA keeps Vo the same as with R6, more pushes LEDS VF a little, like +0.1V Vo

 

[AndrewT]

How can we wired the JFET: d+g one leg and s the other leg or etc...? wich JFET: sk117, sk170, etc?

Idss is measured with G+S and D as input.

This operates in a circuit as well and gives a good CCS.

One would not normally connect D+G and use S as output.
Except that jFETs are reputedly virtually symetrical. One can swap D & S and get virtually the same performance, particularly with those intended for RF duty.
But this would be D+G and S as input, not output.

 

[merlin el mago]

@AndrewT
Thanks for the explanation Andrew, your comments are wellcome and very useful to learn.

@Salas
Min. Idss SK117GR is 3.08mA, could I use?

 

[merlin el mago]

@Salas
The Flip Flop draws 10mA & the DIYINHK isolator 8mA so total 18mA, is very low consumption for the Reflektor-D?

 

[merlin el mago]

Have I to increase R1 2 ohms?

 

[Salas]

Yes 3mA IDSS is good. Only check the Vout is still safe as it should become slightly more.

The Ref-D does not care about minimal to work steadily, only know that you can use less CCS as the spare current becomes more sufficient with little load.

 

[Salas]

Have I to increase R1 2 ohms?

2.2 even

 

[merlin el mago]

Thanks Salas.

 

[merlin el mago]

After changing R1 for 2R (I don't have 2R2) and the SK117GR for R6, now Vout 5.158VDC current 316mA (0.631V across 2R). Some pics:

1st left connected the FF & isolator both powered R-D
2nd BiB only powering Amanero
3h connected only FF without isolator powered R-D

 

[merlin el mago]

Only isolator powered R-D

 

[Salas]

I don't see anomalies, only more system noise on rail when FF is on

 

[merlin el mago]

I arrived the same conclusion Flip Flop generates noise as listened.

 

[Salas]

BTW, you can see best when using the ground spring instead of the crocodile wire on the probe. Probe's GND wire is an antenna.

An externally hosted image should be here but it was not working when we last tested it.

 

[merlin el mago]

Where can I buy, is to be installed at the probe, how much cost?

 

[Salas]

I arrived the same conclusion Flip Flop generates noise as listened.

Maybe needs an RCRC filter?

 

[merlin el mago]

Where: between the PSU & the R-D, wich values?