Capacitor rules

[Daniel]

Hi folks I'm really new with electronics. Doing a massive project for a
retro computer system and, as a prong of this project I'm attempting to
locate a modern equivalent of the board components. Enter the tantalum
capacitor. Having gone to digikey, mouser, and newark none of them seem
to have the item I'm looking for in stock.

What are the rules about alternate values? The tantalum cap I'm looking
for, according to the service manual, has the following rating:

1uf,10v, +-20%.

The DIP style cap that the board uses isn't in stock anywhere so would I
be able to substitute this cap for 1uf, 20v, +-20%?

Thanks,

Daniel

[Phil Hobbs]

Going up in voltage rating is fine. There might possibly be an issue if
the effective series resistance (ESR) is higher, but all solid tants
have highish ESR anyway, so it's unlikely to make a noticeable difference.

(Polymer tants are a different animal.)

Cheers

Phil Hobbs

[Jasen Betts]

On 2023-03-01, Daniel <m...@sc1f1dan.com> wrote:
> Hi folks I'm really new with electronics. Doing a massive project for a
> retro computer system and, as a prong of this project I'm attempting to
> locate a modern equivalent of the board components. Enter the tantalum
> capacitor. Having gone to digikey, mouser, and newark none of them seem
> to have the item I'm looking for in stock.
>
> What are the rules about alternate values?

lower percentage good, higher voltage good.
same or close capacitance good,
sometimes more capacitance is good.

> The tantalum cap I'm looking
> for, according to the service manual, has the following rating:
>
> 1uf,10v, +-20%.
>
> The DIP style cap that the board uses isn't in stock anywhere so would I
> be able to substitute this cap for 1uf, 20v, +-20%?

DIP: I guessing you mean radial pins.

With tantalum going up in voltage leads to improved reliability
if this is a 5V or 8V supply decoupling capacitor the 20V part is much
better suited.

On the other hand inexpensive 1uF ceramic capacitors are now available
and might be an even better substitute (even better reliability), but
that depends mostly on the power supply being able to start with the
reduced series resistance presented by the ceramic parts.

--
Jasen.
pǝsɹǝʌǝɹ sʇɥƃᴉɹ ll∀

[Phil Hobbs]

On 2023-03-01 19:17, Jasen Betts wrote:
> On 2023-03-01, Daniel <m...@sc1f1dan.com> wrote:
>> Hi folks I'm really new with electronics. Doing a massive project for a
>> retro computer system and, as a prong of this project I'm attempting to
>> locate a modern equivalent of the board components. Enter the tantalum
>> capacitor. Having gone to digikey, mouser, and newark none of them seem
>> to have the item I'm looking for in stock.
>>
>> What are the rules about alternate values?
>
> lower percentage good, higher voltage good.
> same or close capacitance good,
> sometimes more capacitance is good.
>
>> The tantalum cap I'm looking
>> for, according to the service manual, has the following rating:
>>
>> 1uf,10v, +-20%.
>>
>> The DIP style cap that the board uses isn't in stock anywhere so would I
>> be able to substitute this cap for 1uf, 20v, +-20%?
>
> DIP: I guessing you mean radial pins.

BITD you could get tants with actual 0.2 inch, 4-pin DIP patterns.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

[Phil Hobbs]

On 2023-03-01 19:54, Phil Hobbs wrote:
> On 2023-03-01 19:17, Jasen Betts wrote:
>> On 2023-03-01, Daniel <m...@sc1f1dan.com> wrote:
>>> Hi folks I'm really new with electronics. Doing a massive project for a
>>> retro computer system and, as a prong of this project I'm attempting to
>>> locate a modern equivalent of the board components. Enter the tantalum
>>> capacitor. Having gone to digikey, mouser, and newark none of them seem
>>> to have the item I'm looking for in stock.
>>>
>>> What are the rules about alternate values?
>>
>> lower percentage good, higher voltage good.
>> same or close capacitance good,
>> sometimes more capacitance is good.
>>
>>> The tantalum cap I'm looking
>>> for, according to the service manual, has the following rating:
>>>
>>> 1uf,10v, +-20%.
>>>
>>> The DIP style cap that the board uses isn't in stock anywhere so would I
>>> be able to substitute this cap for 1uf, 20v, +-20%?
>>
>> DIP: I guessing you mean radial pins.
>
> BITD you could get tants with actual

0.3

[chuck]

On 01/03/2023 9:06:01 a.m., Daniel wrote:
> 1uf,10v, +-20%.

Digikey has dozens of equivalent part numbers in Through hole 1μF
Tantalum 10V or more, 20% or less and millions of caps , so try again.

There are other parameters for reliability and size. but ESR is not one
of them. These all tend to be OK like low ESR aluminum types with ESR*C
product less than or equal to 10 microseconds.

This is well above the audio bandwidth. f=0.44/RC but we have no way of
knowing how it is used.


1μF,20v, +-10%. < I suggest but if it matters you can also search with
filters for;

Price
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Lifetime @ Temp.
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Size / Dimension
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