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Due to size constraints on a custom PCB, I have opted out for using the smallest type of electrolytic capacitors (3 mm diameter.) However, capacitors in such a small diameter are almost impossible to find.

If I remember my high school books correctly , tantalum caps are actually a type of electrolytic capacitors just with different purpose and their size to capacitance ratio is much better than the electrolytic ones.

I know that they have other advantages, but my biggest concern is is it possible to just use tantalum capacitors instead of ordinary electrolytic capacitors? The circuit in mind is just an ordinary amplifier for an electret microphone using a simple LM386.

Edit : Here is the schematic, I am asking for all the electrolytic capacitors. enter image description here

JRE
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Tommy D
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    Note that tantalum capacitors _are_ electrolytic capacitors. This is a bit of a pet peeve of mine; both aluminum and tantalum capacitors (and niobium ones too, though those are rare) are electrolytic, but people tend to talk about aluminum electrolytics as though they're the only type of electrolytic capacitor out there. – Hearth Apr 05 '19 at 02:21
  • Read [this](https://electronics.stackexchange.com/questions/99320/are-tantalum-capacitors-safe-for-use-in-new-designs) and tell us from there what you don't understand and what factor that might be negatively impact your system including your environment usage requirements, so that we can provide a solution to prevent it. – Unknown123 Apr 05 '19 at 02:26
  • The 0.1uF and 0.047uF can be replaced with ceramic (COG or NPO) caps or tantalum. The 100uF cap can be replaced with tantalum. I am not really sure what C10 is for. It possibly could be ceramic, too (X7R or X5R) but since I don't know what it is doing, I am not positive. – user57037 Apr 05 '19 at 02:53
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    @Unknown123 I went to search for my Q&A on the subject and then saw that you had beaten me to it :-) . Hopefully TommyD will in fact read that and get the point. – Russell McMahon Apr 05 '19 at 05:24
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    @mkeith Curiously, the C10+R1 combination is included on every example circuit in the datasheet but never mentioned or explained. – pipe Apr 05 '19 at 08:56
  • Thank you for the help guys, it really helped me, i hope that this question will be useful for other people also. – Tommy D Apr 05 '19 at 17:01

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Yes, you can change it for Tantalum capacitors. The zobel capacitor can be ceramic or nylon. C7 probably you can't find any of this value 0.1uF but you can change it to 1.0uF this will give some aditional bass to your amplifier; however if you use any ceramic capacitor won't have any problem. I've have made this preamplifiers for my projects with success handling tones for hifi amplifiers.

For hobby purposes you can find this kind of assortments inside an old car stereo, any old VCR, any obsolete FTA, etc.

Fernando Baltazar
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Yes you can use tantalum capacitors for the 10uF and 100uF. The .1 uF and .047 caps can be X7R or even Z5U. If space is very tight and this is not an amp for a radio you can omit R1 and the .047 cap. This zobel network is not essential.

EinarA
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  • not essential? Yet every example shows the Zobel filter or the ferrite bead filter – Tony Stewart EE75 Apr 05 '19 at 04:24
  • Yes,every circuit you see today includes the zobel. But my Nat Semi Audio/Radio Handbook says that they are not required only recommended for use in AM radios. I have used the IC without and not seen any instability. I will let the OP decide whether he wants to risk it or not. – EinarA Apr 05 '19 at 04:36
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    C7 better be not ceramic. Ceramic caps usually have piezoelectric effect, and the amplifier might produce some unwanted noises. – Ale..chenski Apr 05 '19 at 05:25
  • You are correct. I would use a film cap here but assumed that Tommy D wasn't that particular since he seems to be focused on component size. I have used ceramic caps in audio circuits and never noticed piezoelectric effects. Except for one cap that turned into some kind of avalanche oscillator. – EinarA Apr 05 '19 at 06:22
  • Class 1 NP0/C0G MLCC cap could also be used here instead of film. – Unknown123 Apr 05 '19 at 06:33
  • That would address the piezoelectric concerns, but last time I looked at C0G caps of .01 uF I thought they were too expensive. – EinarA Apr 05 '19 at 06:41
  • Yup, less than 3mm cheaply for high C value is quite challenging. For example, 0805 NP0 47nF costs 0.9 USD in cut-tape packaging which I found on digikey [here](https://www.digikey.com/products/en/capacitors/ceramic-capacitors/60?k=&pkeyword=&sv=0&pv2049=u0.047%C2%B5F&sf=0&FV=1c0002%2C440012%2C4401d3%2Cb8356f%2Cb8b8c1%2Cmu0.011%C2%B5F%7C2049%7C0%2Cffe0003c&quantity=&ColumnSort=1000011&page=1&pageSize=25). – Unknown123 Apr 05 '19 at 07:12
  • Yeah, i used film cap for C7 1uF, thank you for the help . – Tommy D Apr 05 '19 at 17:03
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Yes you can, but you are far better off using the TPA321D that occupies far less space and has no need for large caps as it is a bridge (differential) driver.

Tony Stewart EE75
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