How can you tell if your capacitors go bad?
At a cursory glance you can tell if the electrolytic ones are burst and leaking electrolytes but that should be obvious. That or swelling is bad.
>>51992784
Pow
Or the tops bend
Licking them
Preferably when the computer is on
charge it and check if it's holding a voltage
if you hook it up with an ohmmeter it will store a charge (ohmmeter works by applying a test voltage).
make sure you discharge first, touch both leads with a screwdriver to do this
>>51992784
Electrolytic ones are made to blow off their top when they fail as a visual indicator. Some fail without the indicator though
If you hear this sound.
>>51992784
They start wearing leather jackets and blowing cigarette smoke in your face
>>51992866
If you like getting a shocking surprise.
Friend of mine discharges his by dipping them in a glass of water.
>>51992784
ESR meter.
>>51992784
with an ESR meter. you may still have to de-solder them if there are multiple capacitors in parallel.
generally just look for leaking or bulging capacitors. if it's an older piece of electronics, you can almost just assume that the capacitors are bad.
If you're getting paid to know, LCR meter.
>>51992784
Their capacitance goes to zero
>>51992784
When they stop working.
Electrolytic capacitors will sometimes leak or burst. Best way to test is to use a resistor of appropriate value in series and check with a Huntron tracker or other analog signal analyzer to see if an RC curve develops properly. If it's a filter capacitor, run the circuit and test with an oscilloscope to ensure the signal out is sufficiently clean. Don't forget to rule out active devices (such as transistors) as suspects first.
>>51992784
Use one of those multimeter with capacitance measurement. If not and if you want to get super serial or go cheap rout, the two most common method of figuring out capacitance in scientific/engineering literature are to either use impedance frequency response measurement or use IV curve plot. For impedance, you can send it few signals at different frequency, since capacitance has frequency dependent impedance, you can setup some quick ordinary differential equation to solve for the capacitance value. Another is to vary a voltage at constant rate and measure the current, and plot this than take the area of the plot to gain capacitance.
