Capacitors in series.

[TechUser]

I need to use a 0.1µF 10V capacitor but instead I want to use a combination in series of 0.22µF 50V and 0.33µF 50V capacitor to bring it close to 0.1 while applying 4.5V DC wanted to know is this combination will work.


I was also wondering if this part can be used **broken link removed**

instead of this part. Thank you.

Digi-Key - LM358NFS-ND (Manufacturer - LM358N)

 

[Nigel Goodwin]

Well that combination won't give 0.1uF.

Won't 0.22uF do anyway?, what is it for?.

 

[bountyhunter]

I was also wondering if this part can be used **broken link removed**

instead of this part. Thank you.

Digi-Key - LM358NFS-ND (Manufacturer - LM358N)

No. They are different parts.

 

[crutschow]

0.22µF is series with 0.33µF will give a capacitance of 0.132µF, if that's close enough for you.

The LM306p is a comparator and the LM358N is an op amp.

For certain applications an op amp can be used as a comparator, but only if a slow response time is acceptable.

But a comparator can not generally be used as an op amp unless a compensation network is added.

 

[TechUser]

Thanks for everyones replies. I'm trying to build a heart monitor and wanted to keep the parts cost way down with what I have. It needed a 0.1µF capacitor at 10V. So I figured a 0.132µF capacitance from a series of .22 and .33 will do just fine. I am confused about the resistor ratings for. How would you know to use a 1/4 watt vs 1/2 watt? If I was only to apply a 4.5V supply?

 

[crutschow]

I am confused about the resistor ratings for. How would you know to use a 1/4 watt vs 1/2 watt? If I was only to apply a 4.5V supply?

The resistor power is V²/R or I²R.

With 4.5V across the resistor, for example, a 1/4 watt resistor would be OK down to a resistance of 81Ω.