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Topic: Ceramic and Tantalum Capacitors ? (Read 162 times) previous topic - next topic

MuizMahdi

Hi all !

Firstly, i`m new to electronics so please bear with me.

I am trying to make this DIY Muscle Sensor circuit found here: http://www.instructables.com/id/Muscle-EMG-Sensor-for-a-Microcontroller/

And i couldn`t find any 1.0uF Ceramic Disk Capacitors or any 1.0uF Tantalum Capacitors, but i could find 1.0uF Electrolytic capacitors, my question is , what difference would it make if i used the electrolytic instead of the Ceramic Disk and the Tantalum knowing that the Electrolytic capacitor could be polar and non polar while the ceramic is non polar and the Tantalum is polar, also what difference would it make if i used different capacitor values, say 0.01uF ceramic capacitor instead of a 1.0uF ceramic capacitor ?
I know that changing the resistance values for resistors changes the amount of voltage but what about the capacitors ? would the circuit still work fine with 0.01uF instead of 1.0uF ?

Thank in advance :)

LarryD

No technical PMs.
The last thing you did is where you should start looking.

MuizMahdi


LarryD

Post a direct link to the schematic, don't make us hunt for it.


If you have scrap boards look on them for one.
The number 105 on a capacitor means you have found one.



.
No technical PMs.
The last thing you did is where you should start looking.

MAS3

Hi and welcome.

If you have to ask these questions, you're not yet up to handle these parts.
Your level of understanding electronics is very low, your statement about what a resistor does is just partially true (you didn't describe what it does, but the effect it will lead to).
That's not a problem, you're here to learn i assume.
There's a lot of uses for resistors.
There's even a lot more uses for capacitors.
These can't be explained in a single forum post, a huge thread wouldn't be helpful either (due to the size that would be).

For an instructable, that one is quite good.
Most of all it's a commercial for some bio-tech company, but it's still better than 99 % of all instrucables.

Electrolytic capacitors can explode if handled incorrectly, a tantalum will burst into flames, both quite violently.
So be careful not to switch polarities.
Always choose a capacitor that can handle a way higher voltage than you are planning to put across it.
Electrolytic capacitors are a bit larger.
Most of the times you can use electrolytic instead of tantalum, but you'll need a bit more space.

Explaining all possible consequences of changing the capacity of a capacitor is impossible.
It requires studying the schematics to tell you about that.
Schematics are available on that site, but i'll suffice by telling you you need to keep to the original values.

To my opinion, experiments that attach to (your) body, aren't the smartest way to start learning electronics.
Have a look at "blink without delay".
Did you connect the grounds ?
Je kunt hier ook in het Nederlands terecht: http://arduino.cc/forum/index.php/board,77.0.html

MuizMahdi






so could i use an electrolytic capacitor instead a ceramic or a tantalum ?
and what change would happen if the capacitor value changes ? ( i think the gain changes since they are used in amplifiers and filters ? )

LarryD

C4 and C3  are part of filter circuits so leave them as is.



.
No technical PMs.
The last thing you did is where you should start looking.

MAS3

I think you'll be fine using the electrolytic instead of the tantalum.
They are in your power lines (their higher value also hints to that).

Use ceramic capacitors for the smaller values.
Have a look at "blink without delay".
Did you connect the grounds ?
Je kunt hier ook in het Nederlands terecht: http://arduino.cc/forum/index.php/board,77.0.html

MarkT

#8
Sep 25, 2016, 01:26 pm Last Edit: Sep 25, 2016, 01:27 pm by MarkT
The 0.01uF and 1.0uF are parts of the opamp filter circuitry, should be plastic film, not ceramic.
The 10uF decouplers can be electrolytic or ceramic, whatever you have really.

This is an ancient circuit using split-rail supplies rather than a low voltage rail-to-rail opamp
circuit that you'd see now, so you may find a better one.

Its also doing a lot of signal processing in hardware rather than software, which is also
very old-hat.  6 opamps in a row is a record, I've never seen quite that many before!
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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