Are you aware of the things that start the engine of your car and offer electrical current to your vehicle? What about those things powering your cell phone, laptop, tablet, or other handheld devices? All those items have a battery, and your HVAC system is no different to it. Remember that the battery keeping your HVAC motor running is what we refer to as the capacitor.
What is a Capacitor?
A capacitor is measured through different ratings: voltage and microfarads.
- Voltage
It is the amount of electrical current moving through an electrical system. That’s quite the same to a garden hose in that the greater the water pressure you turn on. The more water comes out on the hose’s end.
The same thing applies to electricity. The greater the water pressure of the hose goes, the quicker the water moves throughout the hose—the greater the voltage rating on the capacitor, the faster the electrical current moves.
- Microfarad
A microfarad (MFD) rating is a term utilized to describe the level of capacity of the capacitor. That indicates the greater the microfarad rating, the more electrical current it can keep. A standard capacitor could also range from 5 microfarads to 80 microfarads.
Are you currently looking at your capacitor, and you can’t locate the correct rating? Take note that it might also look like µF too on your digital multimeter.
Some different types of capacitors are available today, and each of them have a unique yet slightly different purpose. For instance, a single-run capacitor regulates the motor (that could be on your air conditioner or furnace), and a dual-run capacitor runs the compressor and motor on your air conditioner.
You will also find a start capacitor, often referred to as a hard start kit. This helps jump-start the compressor and kick it into run mode, devoid of putting a huge amount of wear and tear on the run capacitor.
What is the Symbol for Microfarad in a Multimeter?
The microfarad, often symbolized as µF, is a unit of capacitance that is equal to 0.000001 farads. Keep in mind that the microfarad is the moderate unit of capacitance. In audio frequency and utility alternating current, capacitors with values on the order of 1 µF or more are very much common.
A smaller unit at radio frequencies, the picofarad, is often utilized. The unit is equivalent to .000000000001 µF.
In radio frequency scenarios, the capacitance often ranges from at least one pF to 1,000 pF in tuned circuits and from approximately 0.001 µF for bypassing and blocking. On the other hand, capacitances range from at least 0.1 µF to 100 µF at audio frequencies. Capacitance could also be as high as 10,000 µF in power supply filters.
What are the Terminals of a Capacitor?
You will find two terminals in a capacitor: negative and positive terminals, also referred to as cathode and anode accordingly. Based on the polarity of the terminal, you will find two types of capacitors:
- Polar Capacitors
These are also called electrolytic capacitors that use electrolytes as one of their terminals to boost the charge storage capability. It also has higher capacitance than non-polar capacitors. The plates of a polar capacitor are polarized.
While using this, you must check for the polarity of the terminal. Remember that the anode terminal must be kept at a higher voltage compared to its cathode terminals. Reversing its polarity can ruin the capacitor.
In short, make sure you attach the positive with the positive terminal and the negative with the battery’s negative terminal.
- Non-Polar Capacitor
A non-polarized capacitor does not have a polarity. You won’t find any big difference between its terminals, as both terminals could function as anode and cathode. Moreover, non-polar capacitors have a low capacitance, which ranges from few Picofarads to few microfarads.
You won’t see negative and positive terminals too. The terminal linked to the positive terminal of the battery functions as an anode. The terminal linked to the negative terminal of the battery functions as the cathode. Replacing the battery’s polarity doesn’t influence the capacitor.
Practical Tips for Testing a Capacitor with a Multimeter
Remember that capacitor often becomes an unsung hero of electrical circuits which store potential voltage for being released on demand, nearly similar to a battery. The capacitor is typically disregarded until one goes bad, causing an entire device to malfunction or fail.
Digital multimeters are very practical to test whether your capacitor is holding a charge. You can do that process quickly and easily. That is why this guide will also try to offer you some practical tips on how you can test a capacitor with a digital multimeter.
- At the first step, make sure you discharge the capacitor. You can connect two leads of the capacitor by using a wire. You can jump them and discharge any stored voltage.
- For the next step, ensure you set your digital multimeter to get the reading in the high ohms range. It can be somewhere more than 10K and 1M ohms.
- For the third step, make sure you touch the multimeter leads to corresponding leads in your capacitor. Normally, a capacitor is directional, so that you would like to be confident in determining the positive and negative leads.
- For the fourth step, observe the display of your digital multimeter. The display will read one of the two results. If the reading started at zero, then it means it should start moving toward infinity, quickly settling there because of the infinite charging from the multimeter’s battery. The capacitor is surely in good working condition.
Nevertheless, what about if you find that your multimeter stays at zero? Then remember that you’ll know your capacitor is not charging. Hence, it means it’s bad.
- For the last step, check the results by utilizing a known working capacitor of the same kind in a way to make up for any anomaly with the digital multimeter.
Final Thoughts
By following the tips mentioned above, you can easily test your capacitor using a digital multimeter and be able to use the information you learned about the symbol of a microfarad. We hope you find this guide educational and informative.
