1K Potentiometer connected to AD712 is getting warm to touch

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pavjayt

Member

• Sep 3, 2015

• #1

I have an AD712 that has a 1K pot connected to its POS_2 input. After a while the POT is getting warm to touch. Am I not using the right value for POT?

POT is connected to 3,4,5 pins of the header shown in picture.

Supply voltage: ±15VDC
POT connections: Pin1 - -15VDC, Pin2 - POS_2, Pin3 - 15VDC

Any suggestions?

thanks

 

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Ian Rogers

User Extraordinaire

Forum Supporter

Most Helpful Member

• Sep 3, 2015

• #2

30V / 1000 = 30mA that's 900mW.... If your pot is rated at 2W, it will get warm, If its rated at 1W it will get very warm... If you use a 10k it will be better

 

P

pavjayt

Member

• Sep 3, 2015

• #3

Thanks for your quick reply, how about a 20K pot? I have tons of those.

thanks

 

Ian Rogers

User Extraordinaire

Forum Supporter

Most Helpful Member

• Sep 3, 2015

• #4

All depends on the impedance input of the ad712... You'll need to check the datasheet..

 

P

pavjayt

Member

• Sep 3, 2015

• #5

From its datasheet, it says
INPUT IMPEDANCE
Differential 3×10 12 ||5.5 Ω||pF
Common Mode 3×10 12 ||5.5 Ω||pF

 

Mikebits

Well-Known Member

• Sep 5, 2015

• #6

The AD712 is an Op Amp so it is high impedance on the input.