stupid question

[realizewhoitis]

if im looking at a layout what does VR stand for?

[snarblinge]

depends on the layout.

it's either joined to the other VR points and i don't know what it stands for in that case, voltage reference or something

or its Variable Resistor then its a pot.

or the person made up a name for something, all my early notes have transistors as TR1 Tr2 etc.

can you link us to a layout

[JKowalski]

Usually Vr or Vref is the Voltage Reference as snar said aka a virtual ground. It is typically used to create a "fake" ground halfway between the positive and negative voltages in a non-split supply (ex. 0, 4.5v, 9v.... or -9v, -4.5v, 0v.... or 0v, 10v, 20v.... the middle voltage of each being the Vref and the "virtual ground". Your signal rides on top of this virtual ground instead of the normal ground so that the circuit can deal with voltages below and above the signal... If you did not have it and tried to use say an op amp to porvide gain to a signal about 0v but you only had 0v and 9v, you would not be able to because you have no power supply that can deal with those negative voltages.


That is, unless the VR is something different entirely but that ^ is what it typically means.

[realizewhoitis]

here is a link to the layout im talking about

http://www.aronnelson.com/gallery/main.php/v/MarkMs-Gallery/album15/album76/sparkleboost_201_LAYOUT.gif.html

[Thomeeque]

Variable resistor (resistor trimmer) here..

[Renegadrian]

Yes it's a trimmer (variable resistance) - which is mandatory in the sparkle boost, if you want to swap trannies.
I tried it with 2n5457 and j201, and they need really different bias voltages, at least on my build...I had to turn it quite a bit while changing trannies!

[realizewhoitis]

thanks for the help guys. i thought thats what it was but wanted a second opinion. again thanks!

[realizewhoitis]

Yes it's a trimmer (variable resistance) - which is mandatory in the sparkle boost, if you want to swap trannies.
I tried it with 2n5457 and j201, and they need really different bias voltages, at least on my build...I had to turn it quite a bit while changing trannies!

which tranny did you end up using?

[Renegadrian]

As in other circuits, I am a bit more for 5457, so I have one in it.

[realizewhoitis]

As in other circuits, I am a bit more for 5457, so I have one in it.

awesome ill try it out too. thanks