I'm testing my non-reacting circuit with a multimeter, but I don't know if I have to discharge my capacitors first or not. I use two capacitors: 0,1 uF and 560 pF.
Would a charged capacitor react differently to a continuity test than a discharged
capacitormultimeter
Related Solutions
The OL is supposed to tell you that you have overloaded the multimeter in some way. If you look at the datasheet or the specifications of the multimeter you linked, you will notice that it has a capacitance range of only up to 100µF. So the capacitors you are trying to measure are too big (if they are good).
Another overload condition is a short circuit of the leads, it can be imagined as a infinitely large capacitor.
A note on the autoranging with overload conditions: it may take more than 3 seconds to get to the right reading as the multimeter tries the actual measuring range, detects a too big value, switches to the next, detects an overload, until it is at the largest range. I just tried this with a top range Gossen Metrawatt Energy and it took roughly 5 seconds before I got a reading on a 22µF capacitor. Before it would display OL. My HP/Agilent/Keysight 34410A takes around 8 seconds to get the reading, but the display freezes before displaying something.
When you are measuring capacitance with normal leads you might want to hold them as steady as possible and not closely parallel together. Another way is to tape them together and use the Zeroing function of the meter to cancel the lead capacitance out. Additionally you should try to remove your hands while measuring as your body will have a significant effect on the measurement.
A defective capacitor might end up at 30nF, I've taken apart the power board of my LCD monitor and there were some really bad caps, also specified for several hundred microfarad and now in the nanofarad range. Another good indicator for a defective capacitor is the increased ESR (equivalent series resistance), but only specialized LCR meters will give you that value.
The continuity function is designed to give an audible indication of resistance that is less than some threshold value.
To be useful, it will be designed to respond much more quickly than the display so that a tech can quickly 'buzz out' wiring and such like without waiting for the reading to settle or even taking his or her eyes off the test probes. It's specifically designed so that the voltage does not turn diodes on, it won't respond to resistors above a certain value and so on, so that it (usually) responds to just a fairly solid electrical connection.
The values will vary somewhat by manufacturer, but here is an excerpt from the Fluke 177 DMM manual:
As you can see it has hysteresis and a pulse stretcher that allows brief breaks to be detected. This is done by circuitry that is mostly operating in parallel to the main ADC function. Some crummy cheap meters have a continuity beep that is dependent on waiting for an ADC result, but they are not very useful. Avoid!
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Best Answer
Yes, but with caps that small it should not make a difference. Generally your meter measures continuity by applying a small current and then measuring the voltage drop. A short circuit will produce a very small voltage drop. If you connect a large capacitor that's discharged, this current will charge up the cap. As a result, it might take a while for the voltage on the cap to rise above the 'short circuit' threshold, so the meter may read the cap as a short circuit for some time while the cap charges up. This will only be noticeable if your cap is at least 100 uF or so. If the cap is already charged, then the meter might just read the cap as 'open'. However, I would be careful about measuring large charged capacitors in continuity check mode as it is possible that they could damage the meter and/or give you a nice shock. With caps smaller than 1 uF, it won't make much difference, and they were probably already discharged by the circuit anyway.