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| Resistance on my Extech 380193 LCR meter |
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| Dan Moos:
Since I don't believe this meter measures ESR, when I'm measuring a reactive component and have 'R' as my secondary meaurement, exactly what resistance am I reading? Also, this meter only has 1k and 120 Hz freq settings. To me, that seems like quite a limitation. 1 k seems awful low to me. Is this reason enough to find a better one? My interests run the gamut of the hobby, including wanting to dabble in RF. |
| Martin72:
Hi, 120Hz(one way rectified mains frequency) is more for the "high" value capacitors/inductors, 1khz is a very common testfrequency, but will be too low when you want to determine components for RF use. A meter up to 100khz or more should be suitable. The higher the testfrequency, the more expensive the meter will be. Edit: --- Quote ---Since I don't believe this meter measures ESR, when I'm measuring a reactive component and have 'R' as my secondary meaurement, exactly what resistance am I reading? --- End quote --- You could check it in this way: Displayed Capacitor value, when you use the formular for XC = 1/2*pi*f*capacity and the result is more or less similar to the displayed resistance, then it´s not the ESR. |
| Dan Moos:
--- Quote ---You could check it in this way: Displayed Capacitor value, when you use the formular for XC = 1/2*pi*f*capacity and the result is more or less similar to the displayed resistance, then it´s not the ESR. --- End quote --- So you are suggesting its reading the XC at the freq I'm set for? The numbers don't work for that. |
| srb1954:
--- Quote from: Dan Moos on June 17, 2023, 11:06:36 pm ---Since I don't believe this meter measures ESR, when I'm measuring a reactive component and have 'R' as my secondary meaurement, exactly what resistance am I reading? Also, this meter only has 1k and 120 Hz freq settings. To me, that seems like quite a limitation. 1 k seems awful low to me. Is this reason enough to find a better one? My interests run the gamut of the hobby, including wanting to dabble in RF. --- End quote --- It does measure ESR of the component under test when set to the SER mode. You can do a simple experiment: Measure an electrolytic capacitor and note the C and R measurements. R is the ESR of the capacitor. Add another 1 \$\Omega\$ resistor in series with the capacitor and you should note that the resistance reading has increased by 1 \$\Omega\$ indicating that the ESR has increased because of the additional series resistor. On the 1kHz frequency setting this meter has a resolution of 0.1pF and 0.1uH so it is suitable for most component measurement applications. Where it is not suitable is for measuring the D or Q of RF components at somewhere near their normal operating frequency. As the losses in most components increase with frequency the D and Q readings at 1kHz will not accurately represent the actual losses seen in real operation. For improved accuracy of D and Q readings at higher frequencies you will need a RF bridge, which is considerably more expensive than the average hand-held LCR meter. Or you could use a VNA with a component test fixture. |
| Dan Moos:
--- Quote ---You can do a simple experiment: Measure an electrolytic capacitor and note the C and R measurements. R is the ESR of the capacitor. Add another 1 \$\Omega\$ resistor in series with the capacitor and you should note that the resistance reading has increased by 1 \$\Omega\$ indicating that the ESR has increased because of the additional series resistor. --- End quote --- I just tried what you said, but with a 150p ceramic and a 1k resistor. Meter set for capacitance, series, 1 Khz R in the secondary measurement spot. The resistance did jump by 1k. But at 120 hz, the R value went up over 10 times. Is ESR that freq dependent? |
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