Sallen Key Low Pass Filter, bandpass filter

[bertus]

Hello,

I would connect the Rlo to the REF.
You can likely use one buffer for at least 4 filters.

Bertus

 

[Maglatron]

Sound as a pound!

 

[Maglatron]

along with -V

Hello,

I would connect the Rlo to the REF.
You can likely use one buffer for at least 4 filters.

Bertus

 

[Martaine2005]

I suspect your next few hundred posts might put that to the test........

 

[Maglatron]

Just went to play pool for a bit, now I'm going to get on with the designing 16 filters
one more practical question will 16 bar graph type LED's fit on one of these, side by side

 

[Maglatron]

would you put -V to REF aswell?

Hello,

I would connect the Rlo to the REF.
You can likely use one buffer for at least 4 filters.

Bertus

 

[bertus]

Hello,

No, The V- should go to the - of the 12 Volts.
The Rhi could be a value between Ref and +12 Volts.

Bertus

 

[Maglatron]

ok so please can you do an example in schematic picture, also how to cascade in bar graph mode please

 

[Maglatron]

could you draw on to the image above how to wire it if you can? cheers

 

[Maglatron]

how do you make it between REF and +12V, resistors??

The Rhi could be a value between Ref and +12 Volts.

 

[Maglatron]

I'm looking at the datasheet, and it says to connect Rhi to pin 7 of the LM3914 how do you make The Rhi be a value between Ref and +12 Volts.?

 

[Maglatron]

just to clafify at this point is the REF virtual voltage 6volts

 

[Maglatron]

Hello,

Yes, The point called REF is the virtual ground.
All points called REF are connected together.
The ground is lifted to about hlf the powersupply.

Bertus

This tells me yes! I think

how do you make it between REF and +12V, resistors??

still wondering...

 

[Delta Prime]

yeah I'm in hosptal so the hospital internet restrictions are out of my control, I can't even download a VPN!

I got my sister to sign up to allaboutcircuits for me and this site did not require email validation at all!

You brought it up normally,this is private information and does not apply for acquiring information but in its proper contents of kindness and apathy, things I do not wish to lose if I'm fortunate enough to grow old.
The links below are directly related to your query!

LED ‘Graph’ Circuits

Here's a variety of practical LED dot-graph and bar-graph analog-value display circuits.

www.nutsvolts.com

https://diyodemag.com/education/the_classroom_the_lm3914_ic

 

[Maglatron]

I don't understand what you just said but thanks for the link mr prime I want to know how do you make the voltage on Rhi between REF and +12V, resistors?? I will read the entire article and if I still don't understand I'll check back looks like good info, cheers

 

[Delta Prime]

I don't expect you to understand it wasn't meant for you or the kindest person I've never ever met. A kitty cat with the heart of a lion.
You must read it. I would just be repeating what has already been said. I would start with the diode magazine first it'll give you a shortcut for the reff and doing the math easy peasy lemon squeezy.

 

[Maglatron]

I've read the stuff on LM3914 how would I hook this up if I connected the pin 4 Rlo to REF of the buffer circuit how would I set the Rhi to be inbetween the REF and +12v

 

[Delta Prime]

I've read the stuff on LM3914

Lie to the hospital nurse not me...
The reference voltage can be programmed from between 1.2V and 12V. Unless the voltage divider is being externally manipulated, RLO is connected to ground and the voltage reference is fed to the RHI input. These are the two ends of the voltage divider, which divides the reference voltage into ten equal voltages, determining the threshold for each step of the display. For example, at 1.2V reference, each LED represents 120mV if input signal increases. If the reference voltage was set to 12V, each LED would represent a 1.2V increase in the input signal.
The REF OUT pin has a constant, nominal 1.25V between it and ground.

https://diyodemag.com/education/the_classroom_the_lm3914_ic

 

[Maglatron]

I think you missed a bit, I am going to be connecting the Rlo to the REF virtual ground of the buffer wich is 6V, and the -V will be connected to ground, Rhi should be between this REF voltage (6V) and +12V so I choose (9V), how do you wire it??

Hello,

No, The V- should go to the - of the 12 Volts.
The Rhi could be a value between Ref and +12 Volts.

Bertus

 

[Maglatron]

how do you make it between REF and +12V, resistors??

bertus, I feel you understand the problem a little better, can you shed any more light on this matter please? if im supplying Rlo with the reference ground from the the buffer circuit, how do I set the Rhi value to say, 9V? cheers