# Calculating voltage based on schematic

Discussion in 'Electronic Basics' started by Chris, Feb 9, 2005.

1. ### ChrisGuest

So, I know that this is basic electronics, but I'm still a neophyte,
so I need to ask. I need to learn to calculate the expected voltage by
looking at a schematic, and subsequently how modify the schematic to
deliver a different voltage. Can anyone either explain it, or anyone
suggest an in-depth website or book (websites are wayyy easier for me
though)? Thanks

-Chris

2. ### Rheilly PhoullGuest

Sure, you look at the schematic and note the values of the components and
associated voltages etc and using those you calculate the expected values of
voltage/current etc.
To modify the circuit you calculate the values of the components to produce
the different voltage required. If you pay attention in class you should be
able to do this.

3. ### ChrisGuest

heh, thanks

unfortuantely this is my class. ooks, internet texts, and soldering
ron and my workbench. How do I make those calculations though? Where
do I start? Thanks

-Chris

4. ### John FieldsGuest

---
Since you're talking about schematics, why don't you post one and then
ask a specific question that's related to that schematic?

So far what you're asking is general enough that trying to answer
whatever it is we think you have in mind is likely to be a waste of
time. If you don't know how to draw schematics using ASCII characters
so you can post them to non-binary newsgroups like this one, you can
post binaries to alt.binaries.schematics.electronic. or to a web site
somewhere.

There's also a free ASCII schematic drawing package you can download.
The URL escapes me, but I'm sure if you're interested someone with the
URL close at hand will post it for you.

5. ### YDGuest

Book on basic DC circuits, bunch of batteries, bunch of resistors,
DMM, protoboard to hold it all together. Do all the math on papyrus
and stylus, calculators are strictly verboten.

- YD.

6. ### Terry PinnellGuest

The most popular one is AACircuit, developed by Andreas Weber,
www.tech-chat.de

7. ### Robert MonsenGuest

The most recent version has the LTSpice -> ascii thing built in. I
haven't used it, so I don't know how well it works.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

8. ### corGuest

The basics?

to "calculate the expected voltage by
looking at a schematic, and subsequently how modify the schematic to
deliver a different voltage. "

Try simulation. SwCAD Is free.

9. ### ChrisGuest

Thanks for the response,

The problem is I don't have a schematic for it yet, and it is
possible, I may not get one. The project is to modify a power supply
to a large scale recording console for use on a different board. I'm
being supervised and tutored on it a bit, however, I'd really like to
understand math and thought process behind "we need this resistor here
and this value of cap there" and have ageneral understanding of wat I'l
be doing before I pop the chassis and go at it.

Hope this helps a bit wiht understanding my question

-Chris

10. ### John FieldsGuest

---
It does, but it doesn't help to get you any answers. For example, I
could say that a resistor is used as a current limiting device, or to
determine the frequency of oscillation of an oscillator, or to set the
bandwidth of a resonant circuit, or to adjust the output from a
voltage divider, or to heat up a crystal oven, or to set the center
frequency of a filter, and that would all be true, but unless you had
a specific circuit in mind, it would be pointless to guess about what
you wanted.

11. ### Kitchen ManGuest

I'm having a hard time understanding why your curriculum did not teach
you math before getting into circuit analysis. Did you skip a class?

12. ### Kitchen ManGuest

Cut the kid a break. Let him use a slide rule. <eg> Seriously, this
sounds like a great suggestion; I'd add that he should also buy some
capacitors and switches and have some real fun. "Teach yourself
derivatives in three easy lessons."

13. ### ChrisGuest

Heh,

curriculum? I'm a musician and studio rat who likes to tech his own
board. No formal training other than being shown ho to solder in
exchange for a case of beer. I did forget a very important "the,"
though. So it should have read "I would like to understand the math
and thought process behind. . ."

At any rate, I'm a blank slate here. Following schematics and jumping
into a mixing console with an expander and meter isn't all that
difficult, but swapping out the guts of a power supply to get a
different voltage on the "out" ends, is a bit more difficult, at least
to me, right here and now.

The simulation wa great, thank, Ill start workig with ohms law and
grab some old PC boards we have lying around the studio that are slated
for trash. try to blow somethings up.

-Chris

14. ### Kitchen ManGuest

That's a good start. When I was about eight, I plugged a speaker into a
wall outlet, because I wanted to hear what electricity sounded like.
Not that I recommend such an experiment, but it was certainly a learning
experience. =8-0