Determining tantal cap. exactly?

[Bob J.]

Hi all,

Question 1:
Is it possible that changed tantal cap from [email protected]
to 22uF@10V, when to increase rated voltage?

Please check below
http://my.dreamwiz.com/jyeonsuk/qna/q_tantal_cap_47_6v3_22_10v.pdf

Question 2:
How can I determine the value of tantal cap. exactly
when input volts is 5VDC.

Thanks,

 

[Eeyore]

Hi all,

Question 1:
Is it possible that changed tantal cap from [email protected]
to 22uF@10V, when to increase rated voltage?

Please check below
http://my.dreamwiz.com/jyeonsuk/qna/q_tantal_cap_47_6v3_22_10v.pdf

Question 2:
How can I determine the value of tantal cap. exactly
when input volts is 5VDC.

Christ ! You're clueless !

Thank heavens we in the west have more brains than you Koreans. At least there's
some hope for our jobs in the longer term.

Graham

 

[Phil Allison]

"Eeyore"
"Bob J."

Christ ! You're clueless !

Thank heavens we in the west have more brains than you Koreans. At least
there's
some hope for our jobs in the longer term.

Graham

** Phew - I just checked to make sure.

Thank god he is only South Korean.





........ Phil

 

[Joel Kolstad]

Question 1:
Is it possible that changed tantal cap from [email protected]
to 22uF@10V, when to increase rated voltage?

Yes. Why don't you put 2 47uF, 6.3v capacitors in series and calculate what
your new "compound" capacitor's capacitance and voltage rating is (assume
ideal components). If you can't do this, you shouldn't have been tasked
with this problem in the first place.

Question 2:
How can I determine the value of tantal cap. exactly
when input volts is 5VDC.

Depends on how precise you need to be... if you don't need more than, say,
+/-10% readings, just charge the cap to 5V, build something like a 1mA peak
triangle constant current generator, and watch on a scope how the voltage
changes as it integrates the current --> V=1/C*integral of I with respect to
time + V0.

 

[Eeyore]

"Eeyore"
"Bob J."


** Phew - I just checked to make sure.

Thank god he is only South Korean.

....... Phil

Too damn right mate !

Graham

 

[John Fields]

Hi all,

Question 1:
Is it possible that changed tantal cap from [email protected]
to 22uF@10V, when to increase rated voltage?

---
I don't really understand your question, but if you're asking if
it's OK to substitute a 22µF/10V cap for a 47µF/6.3V cap if you only
need 22µF but you need the higher voltage, the answer is yes.
---

Please check below
http://my.dreamwiz.com/jyeonsuk/qna/q_tantal_cap_47_6v3_22_10v.pdf

Question 2:
How can I determine the value of tantal cap. exactly
when input volts is 5VDC.

---
View in Courier:


12V-------------------+--------+
| |
[10K] +---|--[10K]--+
| | | |
ACIN>--[10µF]--[10K]--|----+--|-\ |
| | >-+-----+-------+
+-------|+/ | | |+
| | | [100µF] [CUT]
| | | | |C1
[LM385-5] | [8k2] +->E1 +---->E2
| | | | |
| | | [10K] [100R]
| | | | |R1
GND>------------------+--------+---+-----+-------+---->GND

Set ACIN so that E1 = 100mV

Solve for the current in R1:


E2
I1 = ----
R1


Solve for the impedance of C1R1:


E1
Z = ----
I1


Solve for the reactance of C1:


Xc = sqrt(Z² - R²)


Solve for the capacitance of C1


1
C = ----------
2pi f Xc


The error in the solution will be increased by the ESR of C1.

 

[Bob J.]

John Fields:

need 22µF but you need the higher voltage, the answer is yes.

1
C = ----------
2pi f Xc

Thanks a lot