Tantalum Cap Question

[jb33]

Theoretically, why would a tantalum capacitors anode EVER be connected to ground?

 

[danadak]

When cap cathode is at a V <= 0V, eg. negative with respect to ground. Eh. bypassing a negative supply V
for example.

Regards, Dana.

 

[jb33]

Interesting; I could see bypassing a negative supply.

 

[Nigel Goodwin]

Connecting a tantalum capacitor's anode directly to ground is almost always incorrect and risks damage due to reverse voltage. They are polarized and require the anode to be positive relative to the cathode. While rare exceptions might exist in specialized circuits, standard practice is to avoid this configuration.

Sorry, but you are completely wrong, or have misunderstood what has been said?.

It's standard practice, and not at all specialised - if you have a negative voltage rail (very, very common) then the decouplers on that negative rail have their anodes connected to chassis (which could also be ground). This leaves the anode positive relative to the cathode, as it should be.

 

[DHolub]

When cap cathode is at a V <= 0V, eg. negative with respect to ground. Eh. bypassing a negative supply V
for example.

View attachment 147394

Regards, Dana.

It's used in this configuration on negative power supplies all the time. Polarity is very important.

 

[Nigel Goodwin]

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