Do I have the idea right?

[monkeykoder]

For those of you who are actually Electrical Engineers is this approximately the schematic for a generalized linear regulator VV mod? The idea here is to provide a place to post and analyze schematics as a way for selecting appropriate parts for a mod.

 

[monkeykoder]

As an example usage of the possible thread. For the above schematic if my understanding of linear regulators is correct we choose some resistor R between vout and vadj and we call Vs the set voltage between vadj and vout we select the pot to go from approximately (3v/Vs - 1) * R and (10v/Vs -1) * R which should give us a VV mod that goes from 3v-10v and at that point all we need to do is select the rest of the parts to fit the design spec?

P.P.S. The transistor is meant to be a generalized idea of a transistor not necessarily the correct one for the given mod.

 

[CraigHB]

A bipolar transistor could do the job, but a MOSFET is the ideal transistor for the application. Since MOSFETS are voltage biased instead of current biased, the schematic would need to be a bit different. Implementing the same high side switch with a MOSFET would require a P-channel device. There would need to be a pull-up resistor and ground switch on the gate instead of a bias resistor on the base.

 

[monkeykoder]

I'll have to look up a lot of the terminology you're using... I took introductory circuits but it had more to do with systems of differential equations than actual circuits...



Is that approximately what you're talking about?

 

[CraigHB]

Yes, that would be the ideal device (P-channel enhancement mode MOSFET) for that circuit and that's the correct wiring. Though, when drawing circuit diagrams, it's always best whenever possible to keep positive connections along a top horizontal reference and negative connections along a bottom horizontal reference. Inputs should be on the left and outputs on the right. It's not imperative you draw schematics like that, but it's sort of an unwritten convention that makes them easier to read for others.

 

[monkeykoder]

I'll have to work on that for the next generic schematic I do I don't exactly think many people will be wanting a linear regulated vv mod.