Hello Everyone ,
Few days back i had posted a question related to an instrumentation amplifier ,
As per suggestions and advice from forum members..i made the circuit...and it works like charm !!!
Now i had ordered 0.47microfarad disc type capacitors and i got 100 electrolytic polarised capacitors ...supplier wont take it back ..
Please review and suggest if i can use 0.47 electrolytic polarised capacitors.
Images :
1) circuit (capacitors C3 and C4)
2)type of capacitors i expected
3)the ones that i got ...

Thank you !!

 

Since one end of C3 is grounded, a polarized cap will be OK if circuit voltages never drop below ground. I didn't take the time to study your circuit to verify that is true. The situation at C4 is even less clear to me. But if the cap is always charged with one polarity, the polarized cap will be OK.

The supplier is acting very badly, if in fact you can prove what you ordered. Most suppliers I've dealt with would let you keep the wrong part and ship the proper ones to you. Otherwise, you'll never go back to them.

 

If the op-amps are supplied with positive and negative supply rails with the circuit ground being half-way in between then, no, you can't use electrolytics in those positions as the input and output of that last amplifier may be either positive or negative depending on the input.

 

It's problematic to use those electrolytics in those two spots.
Afraid you will need to buy some non-polarized caps for that.

 

Since one end of C3 is grounded, a polarized cap will be OK if circuit voltages never drop below ground. I didn't take the time to study your circuit to verify that is true. The situation at C4 is even less clear to me. But if the cap is always charged with one polarity, the polarized cap will be OK.

The supplier is acting very badly, if in fact you can prove what you ordered. Most suppliers I've dealt with would let you keep the wrong part and ship the proper ones to you. Otherwise, you'll never go back to them.

Help us avoid dealing with that supplier in the future. Who from? What part number did you order?

 

Hello Everyone ,
Few days back i had posted a question related to an instrumentation amplifier ,
As per suggestions and advice from forum members..i made the circuit...and it works like charm !!!
Now i had ordered 0.47microfarad disc type capacitors and i got 100 electrolytic polarised capacitors ...supplier wont take it back ..
Please review and suggest if i can use 0.47 electrolytic polarised capacitors.
Images :
1) circuit (capacitors C3 and C4)
2)type of capacitors i expected
3)the ones that i got ...

Thank you !!View attachment 109884 View attachment 109885
View attachment 109886

Use four of the caps you have, connected as follows to make one non-polar cap assembly of .47uF. Be sure to connect + to + on the caps.

 

(Below is incorrect as suggested)
474 = 47 with 4 zeros pF or 47 000 e-12, or 47 nf (e-9) or 0.047 uF (e-6) not 0.47 uf

0.47 uF is a little high for a ceramic cap. Polyester caps are non-polarized and have better tolerances.

Edit:
Thanks Guys. (Migraine): Corrected version.
474 = 47 with 4 zeros pF or 470 000 e-12, or 470 nf (e-9) or 0.47 uF (e-6) or 0.47 uf

 

474 = 47 with 4 zeros pF or 47 000 e-12, or 47 nf (e-9) or 0.047 uF (e-6) not 0.47 uf

0.47 uF is a little high for a ceramic cap. Polyester caps are non-polarized and have better tolerances.

Well 47 and 4 zeros is 0.47 uF alright (470 000 pF). Not unusual for a ceramic cap.

 

474 = 47 with 4 zeros pF or 47 000 e-12, or 47 nf (e-9) or 0.047 uF (e-6) not 0.47 uf

0.47 uF is a little high for a ceramic cap. Polyester caps are non-polarized and have better tolerances.

Wrong.
A cap labeled 474 = 0.47uF (470 nF).

470000 pF

 

There is an error in the schematic in post #1: the inputs of U3 are reversed. As drawn, the circuit will not operate; rather, the positive feedback through R10 will force U3 to latch up, with its output stuck at either the positive or negative supply rail.

 

Wow, nice catch @OBW0549