Finding the right ceramic 1206 capacitors

All the SMD ceramic capacitors look the same and don’t have any markers. How would you know which replacement uF and voltage to buy? I measured the uF while in circuit to be 0.4 and 0.5 even though they look the same. If I took them out of circuit I get zero. I also don’t see any matching uF on Digikey.

Measuring low value capacitors in circuit almost never gives a useful reading due to PCB and other component stray capacitances.

With them out of the circuit, use a lower setting on your capacitance meter and I suspect you’ll find they are low picofarard capacitors. (Edit: deleted pre-coffee range error)

Of course the easy way to identify them is to have the schematic an parts list for the circuit you’re repairing. Some manufacturers will provide a schematic and parts list on request from customers.

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What’s an example of a multimeter or device that can read low capacitance? I thought all multimeters should be able to do it, which now is clearly wrong.

Here’s one possibility:


The lowest range measures up to 6.6nF and it has a resolution of 1pF, although things like lead and stray capacitance will render absolute accuracy to be nowhere near that good, particularly at the lower end of that scale.

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