Simple Newbie Capacitor Question

[Bob Grimm]

Hello,

I'm just getting my feet wet in electronics and have started working
thru Myke Predko's Digital Electronics Guidebook.

Anyhow the projects specify using 0.1uF 16V Tantalum
capacitors.

Neither my local Radio Shack or DigiKey (where I prefer
to purchase my parts) have anything less than 1uF Caps.

Question is can I use 1 uF Caps in place of 0.1uF or am
I competely wrong.

I understand derating the voltage of the capacitors but I'm
not sure if the capacitance HAS to be specific to the project.

Thanks,
BG

 

[scada]

Hello,

I'm just getting my feet wet in electronics and have started working
thru Myke Predko's Digital Electronics Guidebook.

Anyhow the projects specify using 0.1uF 16V Tantalum
capacitors.

Neither my local Radio Shack or DigiKey (where I prefer
to purchase my parts) have anything less than 1uF Caps.

Question is can I use 1 uF Caps in place of 0.1uF or am
I competely wrong.

I understand derating the voltage of the capacitors but I'm
not sure if the capacitance HAS to be specific to the project.

Thanks,
BG

You did not try hard enough.And no, a 1 µf Cap is not the same as a .1µf
cap! Go to www.digikey.com search for capacitor, then Tantalum. Put in the
value (you can use a higher voltage, if physical space allows). One hit I
got, part# 399-1348-ND (0.1 µf / 35V) which is one of many!

 

[Bob Grimm]

You did not try hard enough.And no, a 1 µf Cap is not the same as a .1µf
cap! Go to www.digikey.com search for capacitor, then Tantalum. Put in the
value (you can use a higher voltage, if physical space allows). One hit I
got, part# 399-1348-ND (0.1 µf / 35V) which is one of many!

Most of the projects are 12v and so the specification was to
deregulate the voltage to 16v Caps.

I did indeed see the 35v caps in the list but was hoping to stick
to what was recommended. (16 volt).

I know there is no harm done in using a MUCH greater than required
voltage capacitor. My question was regarding the capacitance.

Thanks,
BG

 

[andrew]

Bob,

Use 0.1uF 'box polyester' or 'disc ceramic' . The parts will be used as
decoupling caps probably 1 per chip package in the circuit. you can also use
down to 0.01uF for this. Value is not too critical for decoupling in 'home '
projects.

Andrew.

 

[Spudley]

I would use a standard 0.1 uF ceramic or poly capacitor instead, as
long as it's voltage equalled or exceeded the spec called for in the
schematic.
0.1uF caps are normally used for bypass purposes "Noise reduction"
within circuits, Tantalums are polarised, and are lower voltage.

 

[miketinte]

It depends on the application. Changing the capacitor value will
change the timing constant and cutoff frequencies, as well as DC
behavior of the circuit. Without knowing what exactly you're using the
cap for, it's hard to say WHAT effect the differenct capacitance will
have on the desired outcome, but it definitely will affect it. Go with
the specified capacitance, there's usually a reason it was chosen.

 

[JeffM]

the projects specify using 0.1uF 16V Tantalum capacitors.

I would use a standard 0.1 uF ceramic or poly capacitor instead
Spudley

I'm with Spudley. Ceramics are cheap (watch the tolerances
--tho if tantalum was originally specified, it's probably not an issue).

Films are a little more expensive but spec'd tighter.

The only reason I can imagine for calling out a 0.1uF tantalum
would be to pack the cap into the smallest possible volume.


Using caps with a higher voltage rating
is akin to putting a 429 into a Ford when the speed limit is 35
--a 2L 4-banger will do the trick.
At idle you just use more gas (cap-->wasted volume, more leakage).