What does Vcc and Vref mean?

T

TheMusicStudent

New member
I'm currently looking at the "Glory Hole" schematic (Attached), trying to simulate it in LTspice. However, there are many connections to either Vcc or Vref. What do these mean?
 

Attachments

@TheMusicStudent — Further 101 reading that might be of interest:

Attempting to breadboard. What is VCC in a schematic?

I would like to try and breadboard the El-Sol (Acapulco Gold) circuit here at home as my first ever breadboard project. I've already made the PCB and it works fine, I figure it's a simple enough pedal so it might be easiest to breadboard since I already own duplicates of each component. I'm...
forum.pedalpcb.com forum.pedalpcb.com
There's a bit of a glossary of power terms in my post, #15. Plenty of other good info from Temol, HamishR etc.

and...

Charge Pump Block Question (TC1044SCPA)

For projects with a charge pump (e.g., TC1044SCPA) for (positive) voltage doubling, why is there a capacitor between pin 4 (CAP-) and pin 2 (CAP+) before connecting to another cap positioned on the cathode of the Schottky diode after pin 8 (V+). Unless there's a negative voltage conversion, is...
forum.pedalpcb.com forum.pedalpcb.com

What's the Big Deal with Power Supplies?

It just makes DC, how hard can that be? Over the course of my engineering career, one of the things I did was design power supplies. The guys who used those power supplies, RF designers, digital designers, precision analog designers, all underestimated the difficulty in designing a power...
forum.pedalpcb.com forum.pedalpcb.com
 
Vref is often used as a kind of ground. Sometimes, but not always, components referenced to Vref can be referenced to ground instead, and sometimes it's better to do so. However knowing when to do so is a dark art and only witches and virgins can tell you.
 
HamishR said:
However knowing when to do so is a dark art and only witches and virgins can tell you.
Click to expand...
Look at how your opamps are connected. If the negative rail (pin 4 on a TL072 or similar) goes to ground, your Vref is going to be half of your positive rail voltage (VCC). If the negative rail is connected to a negative voltage opposite of the positive rail's voltage, i.e. +9V on pin 8 and -9V on pin 4, then your Vref will actually be 0V, or ground.

Vref is still half of the total "swing" between the two rails.

What's halfway between 9 and 0? 4.5

What's halfway between +9 and -9? 0

What's halfway between +18 and -9? +4.5

What's halfway between +15 and -15? 0

There's a rhyme and reason behind it.


*Disclaimer - definitely not a virgin, probably not a witch
 
Last edited:
vigilante398 said:
Look at how your opamps are connected. If the negative rail (pin 4 on a TL072 or similar) goes to ground, your Vref is going to be half of your positive rail voltage (VCC). If the negative rail is connected to a negative voltage, i.e. +9V on pin 8 and -9V on pin 4, then your Vref will actually be 0V, or ground.

Vref is still half of the total "swing" between the two rails.

What's halfway between 9 and 0? 4.5

What's halfway between +9 and -9? 0

What's halfway between +18 and -9? +4.5

What's halfway between +15 and -15? 0

There's a rhyme and reason behind it.


*Disclaimer - definitely not a virgin, probably not a witch
Click to expand...
Very small rocks!
 
You must log in or register to reply here.

Similar threads

M
Chauffeur Overdrive Circuit Question - VREF and Bipolar Supply?
Replies
6
Views
453
mckillacuddy
M
Ctrl4Smilerz
Noob question VCC and VREF
Replies
9
Views
672
Grubb
Grubb
R
So what exactly does True Bypass mean?
Replies
4
Views
412
Rpschultz13
R
M
Translating a Schematic into Physical Reality
Replies
4
Views
331
Mr. Strypes
M
P
Aion Lithium - what does this cap do?
Replies
1
Views
202
benny_profane
B
Back
Top