Newbie Schematic Question

[Baktown]

Greetings all,

Can anyone educate me on what the symbol Vr (in yellow) means on the following schematic?

Also, where would V+ terminate? 

Thanks in advance,

Axl

[PerroGrande]

Vr (or Vref) usually represents the midpoint (reference) voltage required when operating an op-amp from a single supply.

V+ would run to the IC's positive supply pin (and anything else that needs 9v, such as an LED, for example), while its negative supply pin would go to ground.

[Baktown]

That's sort of what I thought, but I see 2 points where Vr goes, and none for V+.

Axl

[GREEN FUZ]

That's sort of what I thought, but I see 2 points where Vr goes, and none for V+.

Axl

It`s just above where you`ve indicated the Vr in yellow.

EDIT: Whoops, should have reread the thread before responding. I know that`s not the answer you were looking for.

[JOHNO]

if the op amp is TLO72,LM833, i would say it goes to pin 8. what opamp is it?

[ambulancevoice]

Vr (or Vref) usually represents the midpoint (reference) voltage required when operating an op-amp from a single supply.

V+ would run to the IC's positive supply pin (and anything else that needs 9v, such as an LED, for example), while its negative supply pin would go to ground.

yeah, ive been wondering what it means too
appy polly loggies, but im a bit lost
so Vr(ef) means half the supply voltage? if you had a 9v supply, Vr would be 4.5v? Yes?

[JOHNO]

thats right alex/jack notice the voltage is comin from the two 10k resistors thats the voltage divider

[MartyMart]

Axl, VR ( Vref ) is the mid point between the + and - voltage, in this case V+= 9v and V-= 0v so VR= 4.5v
On schematics, often not all pins are marked, so it is assumed that you know that for a dual opamp, V+ ( 9v ) is
supplied to pin 8 and V- ( 0v or ground ) is at pin 4
For a single opamp this changes to pin 7 for V+ and stays at pin 4 for V-
Anywhere on the schem where you see a "VR" connection, connect this to your voltage divider, usually the mid point of two
resistors with a cap to ground off the mid point, in this case its the 2 x 10k's
MM.

[Baktown]

Thanks guys!

The op amp is a 4558, by the way.

Axl