Capacitance of SMD resistor

[KonstanU]

I have been surpised when my measurement of SMD capacitance revealed value 500-600 pF (SMD value is 200k).
Who can tell me if it is true or not?

 

[betwixt]

That is unreasonably high and I suspect your measurment instrument is not measuring capacitance but the equivalent reactance. How are you measuring it?

Brian.

 

[KonstanU]

I used Agilent U1241B True RMS Multimeter.

 

[betwixt]

That meter is not really intended to measure capacitance of other types of component than capacitors. There are some meters that use complex phase and voltge measurements to measure capacitance when other component properties are also present but your meter does not.

I think what you are seeing is a false reading caused by the meter being confused by the resistance and mistaking the current flowing through it for charge in a capacitor. Meters normally use one of two common methods, either they discharge the capacitor then see how long it takes to recharge from a known current, or, they apply a known AC voltage at one end and measure the current it passes into a load at the other. In both cases, having resistance as well as capacitance will cause a wrong reading, making the meter think the capacitor is much larger than it really is. A typical capcitance across an SMD resistor will only be 1 - 2 pF.

Brian.