Detecting defective electrolytic capacitors when they are still in the circuit is a difficult and complicated job. The use of an ESR meter to it will allow the technicians to identify the damage is easily and quickly. This device is very important to measure the characteristics of electrolytic capacitors in the form of equivalent series resistance (ESR).
If you want to have an ESR meter can be through purchase in the form of a kit or DIY or buy a device ready to use it online like at Amazon. If you want a simple one, you can make it follow the instructions of the device schematic from tech info on the internet.
The following circuit is a circuit board Digital Metering ESR from Dick Smith Electronics, which can be used as a reference if you want to build yourself a measurement device such as an electrolytic capacitor of the famous Blue ESR meter, or from Bob Parker. However, this device has been discontinued. You can download this product information in PDF format.
How It Works
The work of the device to measure the resistance of electrolytic capacitors straight (as possible) without taking into account the capacitive reactance.
As shown, switch “S1” (actually an electronic switch driven by a microcontroller) alternately connect and disconnect capacitors to test the source of constant current of 0.5 mA, that is 5mA or 50mA (depending on coverage). In practice the capacitor alternately filled with 8ms (S1 in “CHARGE”) and discharged to 492μs (S1 in DISCHARGE position).