Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Using 2 potentiometer pins only for audio in?

Status
Not open for further replies.
J

Johanx2

Advanced Member level 4
Joined
May 13, 2012
Messages
113
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,298
Activity points
2,636
Hi, I have this doubt, what happen if I dont use the third pin of the potentiometer in an audio application? Its just a pin connected to ground, is it really necessary connecting it there? I need to do some potentiometer extensions, and if I can only use 2 pins, then I will use a minor number of total cables.

broken link removed
 

Attachments

  • 5465dfg.jpg
    5465dfg.jpg
    77.9 KB · Views: 119
Last edited by a moderator:

Using only two pins on a potentiometer will not work as a volume control.
1) With 3 pins the pot is a voltage divider with signal control from zero to maximum.
2) The input resistance of the LM386 amplifier IC you show is 50k ohms. Using 2 pins of the pot the signal becomes divided to 50k/(10k + 50K)= 83% for the minimum to 100% for the maximum. You will barely notice the difference in level since 70.7% sounds only a little less. 10% to 20% sounds half as loud and 1% is still very audible.
 

Hi, besides that not being possible in your circuit, one should always tie floating/unused potentiometer pins to the wiper, Bourns have nice app notes. The pdf is one, but not the one I was looking for...


...found it, big book, but worth browsing for specific points of interest.
 

Attachments

  • trmrpmr.pdf
    1.2 MB · Views: 92
  • onlinepotentiometerhandbook.pdf
    22.1 MB · Views: 99
Last edited:
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top