Dear All,
How we can check the capacitor with multimeter probes on PCB or in the live circuit?

 

If you can measure instantaneous current and voltage across its terminals you can calculate value of C from the formula (i=c*dv/dt). May be some company has developed an instrument that can measure R, L or C in "live" circuits but it's difficult if you don't know what is connected to the capacitor. To my knowledge i can't recomend you one.

 

The most practical way to check a capacitor in a live circuit is to understand the role of that capacitor in that particular circuit, and then make voltage measurements and compare those measurements with what your understanding of the role of that particular capacitor tells you. This will lead to a different procedure for each application, but there is no one generic way to do it with a live circuit.

Robert Scott
Real-Time Specialties
Embedded Systems Consulting