A capacitor will store excess electrical energy which it supplies to the central appliance or device in case of power stoppage or shortage. However, when you want to work with a capacitor for a new device, it is imperative that you first discharge the capacitor for safety reasons.
And today’s write-up we will discuss how to discharge a capacitor with a multimeter. Our guideline will also include suggestions on discharging an AC capacitor, from the circuit board and the use of a capacitor discharge tool.
So, don’t miss the chance to know the safe discharging technique of the capacitor.
When we talk about discharging a capacitor with multimeter, there’s often a misconception that arises among us. So, let us first clear one thing-
The multimeter isn’t used directly to discharge the stored energy of a capacitor. Instead, people use it to measure the voltage and power of the capacitor to know whether it is fully released or not.
You can use different tools such as a light bulb or a DIY discharge tool for the process. But everything starts with checking the actual charge of the capacitor.
Make sure you have disconnected the capacitor from its power source. If you work with a capacitor in the car, disconnect the battery. And for home appliances, unplug the device from the power outlet.
You need to set up the multimeter at its highest DC voltage capacity. Since different multimeters come with various DC voltage limit, read the user manual to know the specific DC voltage limit of the multimeter.
Then turn the knob to set the DV voltage in its peak. The highest DC setting ensures you will get the most accurate readings from the capacitor.
Connect the two probes of the multimeter with two heads of the capacitor. It doesn’t matter on which capacitor head you connect the black or red probe or vice versa. Carefully hold the probes on the capacitor lead and check the readings on display.
Depending on the capacitor size, the multimeter display may show readings between a few volts to a few hundred volts. If the reading is above 10V, it is considered dangerous since anything above 10V can provide you with an electrical shock.
The few critical notes for the capacitor voltage readings are:
Now we will discuss different discharging methods of the capacitor using light bulbs, screwdrivers, and discharging tool.
If you have a capacitor bank with a higher voltage value, you may use a light bulb to discharge it securely. The three standard DC capacitor voltages are 100V, 200V, and 300V. You can use a 75W enabled light bulb to discharge these capacitors.
These steps include:
Another easy way to discharge the capacitor is the use of a screwdriver. It is less complicated and doesn’t require any superior skills too.
When you want to discharge a large amount of voltage from the capacitor, applying a discharging tool is recommended. You can DIY create the device.
Things you will need:
The steps include:
You should remember that a discharging tool is simply a small resistor. The wires are connected with the alligator clips to soak the voltage from the capacitor. So, organize all the required items in one location to create the discharging item.
Firstly, wrap the two alligator clips with the electrical tapes. Wrap one clip with black tape and the other one with red tape to quickly identify which is for what ends of the resistor. Then, use a scissor to cut the wire in two equal parts, each 6-inch long.
When you use longer wires, it offers you easiness to connect the ends with the capacitor poles.
Use a wire stripper to clip off about ½” from the wire insulation to bring out the copper wire. Alternatively, you can use a razor blade or sharp knife to cut the insulation carefully. Then, you may use fingers to pull the remaining part of the wire.
Whatever process you follow, make sure you don’t damage the wire.
Once you have brought out the metal portion of the wire, you need to connect its one end with the resistor. You can use solders to touch one end of each wire with one pole of the resistor. Once you have connected the cables with the resistor poles, the other side of each wire is free to attach with the capacitor.
This step is pretty simple. Use the black and red electrical tapes to wrap each soldering points of the wire. It secures the connection from any loose activity. Also, it acts as a safeguard against any accidental electrical shocks.
This time, use your soldering skill to connect the free ends of the wire with the alligator clips. After soldering the alligator clips with the wire, wrap them using the electrical tapes for security.
Place the capacitor on a plain woody surface and make sure it doesn’t move. Now, connect each wired alligator clips with one pole of the capacitor. When the poles are associated with the resistor through the wires, it will quickly discharge the entire capacitor.
Now connect the multimeter with the capacitor probes and check the readings to find out whether or not the capacitor has been correctly discharged. As you set the multimeter at its highest voltage and connect the capacitor, the reading should come below 10V.
If the reading is above 10V, connect the alligator clips correctly and continue the discharging once again.
You can follow these guidelines to accomplish knowing how to discharge an AC capacitor too.
Discharging a capacitor doesn’t need any rocket science knowledge. Neither does it require any expert skills. Nonetheless, when you work to discharge the capacitor with a multimeter, you must be attentive and operate with caution to prevent electric shocks.
Also, note that the multimeter is only used to measure the voltage of the capacitor; it doesn’t have an active role in the discharging project itself. You will need a proper discharging tool or a screwdriver to complete the whole process.