hdspeakerman
Member
I did not read all the other posts but I use mine for making crossovers. Some times you have to unwind an inductor to a certain value. Much needed for that.
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The Importance of LCR Meters
- Thread starter Audiofire
- Start date
I miss those days... The bias Ts I use now have microscopic fairy dust inside for all I know. Way too small for me to build (latest crop is all 70 GHz stuff).
I am torn between some sort of snarky "boys and toys" comment and the desire to stay in your good graces and (more importantly) will. But I think Sir Thomas @Thomas savage has the latter all sewed up (or bottled up).Why? I will be less of an engineer then. Everyone knows that the number of meters you have indicates how good of an engineer you are. I think I have something close to 20 meters around.
I used to bring stuff home from work all the time, but (a) work hours are insane so no time, and (b) I can handle a DMM, but our DSOs cost more than my house, so I'm afraid to sign one out...
Edit: I suppose the proper answer would have been along the lines of "Only two? Noob..."
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OP
- Thread Starter
- #44
I found the B&K Precision 891 that measures up to 100 mF (100,000 uF) within 1% inaccuracy (with an associated price that pretty much restricts it to industry and people who have a life-long interest in electronics). B&K Precision 880 is much cheaper and a good LCR meter, but only measures up to 20,000 uF (with more inaccuracy).
The meters require that capacitors are discharged and the correct way to discharge capacitors is with an appropriate resistor, while short circuiting it is actually one of the failure modes that can happen when it is near the end of the so-called bathtub curve. And there is even a risk of getting a dangerous electric shock if electrician's gloves or similar insulation is not used (the sleeves of aluminum electrolytic capacitors are strictly speaking not necessarily made for insulation).
Source:
NICHICON CORPORATION. TECHNICAL NOTES CAT.8101E-1. Application Guidelines for Aluminum Electrolytic Capacitors.
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If you have an audio interface you can measure components with REW.
Wow, I didn't know this. Kudos to you! I bow my head in awe ...
OP
- Thread Starter
- #47
Measuring before and after with the same music on an audio interface when replacing capacitors is also useful. It is like measuring the capacitors indirectly. Recapping as it is called can be verified as successful with this simple before-and-after measurement on the audio inputs and outputs.
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I assume it would be also really important to measure and know the Fq response at various "stages", digital domain, analog domain and real air sound, in your audio system; I learned a lot through my systematic measurements in this regard as shared in my posts #393 through #409 on my multichannel multi-driver multi-amplifier project thread.
I did it by "cumulative white noise averaging method" by using Adobe Audition 3.0.1 and MusicScope 2.1.0, a simple audio interface TASCAM US-1x2HR, and a measurement microphone BEHRINGER ECM8000 for air sound analysis.
The measurements should be done separately for each channel (for each of the SP drivers) and also for the total signal/air-sound, then you may find and know many features and characteristics of your system for further fine tuning if needed.
I did it by "cumulative white noise averaging method" by using Adobe Audition 3.0.1 and MusicScope 2.1.0, a simple audio interface TASCAM US-1x2HR, and a measurement microphone BEHRINGER ECM8000 for air sound analysis.
The measurements should be done separately for each channel (for each of the SP drivers) and also for the total signal/air-sound, then you may find and know many features and characteristics of your system for further fine tuning if needed.
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I fully agree with you.
Just for your reference, as far as "relative time alignment between the SP drivers" and "fine adjustments in 0.1 msec precision", I recently could establish my own rather primitive but reliable methods as shared in my posts on my project thread;
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-1_ Precision pulse wave matching method: #493
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-2_ Energy peak matching method: #494
- Precision measurement and adjustment of time alignment for speaker (SP) units: Part-3_ Precision single sine wave matching method in 0.1 msec accuracy: #504, #507, #508
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Embarrassing; I use REW now and then, knew about this, and totally forgot about it! Sorry John...
valerianf
Addicted to Fun and Learning
The B&K LCR meter are good equipment that I am using since 15 years at work. You need it a few time each year but there is no other replacement tool.
For audio hobby may be DATS V3 is sufficient as it can measure LCR.
But I never tried it for that purpose.
For audio hobby may be DATS V3 is sufficient as it can measure LCR.
But I never tried it for that purpose.
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Since 2012 the DE 5000 has been 'the' handheld, multimeter style LCR meter. Tons of YouTube Videos about it. Price below 200 bucks.
If you want to buy one these days it might be hard to get. An alternative (that I use myself) is the ET 432:
www.aliexpress.com
Both are no toys and quite accurate. Nowadays there are also more cheap LCR meters that measure more than good enough for the usually very unprecise capacitors.
If you want to buy one these days it might be hard to get. An alternative (that I use myself) is the ET 432:
92.66US $ 73% OFF|Et430 Et431 Et432 Et433 Multifunction Handheld Lcr Digital Bridge Meter High Precision Capacitance Inductance Resistance Meter - Energy Meters - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
Both are no toys and quite accurate. Nowadays there are also more cheap LCR meters that measure more than good enough for the usually very unprecise capacitors.
OP
- Thread Starter
- #53
"In most applications, aluminum electrolytic capacitors – as poled devices – are used with a DC voltage bias of proper polarity with some superimposed AC voltage. Reverse polarities of up to 1.5 V are permissible for short periods of time as the formation of a damaging oxide layer on the cathode only starts at voltages of this magnitude. This is because the cathode foil is covered by an air-oxide layer that corresponds to an anodized dielectric layer with a breakdown voltage of approximately 1.5 V.
"For this purpose, the capacitive component of the equivalent series circuit (the series capacitance C_s) is determined by applying an alternating voltage of ≤ 0.5 V. As the AC capacitance depends on frequency and temperature, IEC 60384-1 and IEC 60384-4 prescribe a measuring frequency of 100 Hz or 120 Hz and a temperature of 20 °C (other reference values by special request).
"The equivalent series resistance of aluminum electrolytic capacitors varies with the frequency of the AC signal. As a result, the ripple current capability, which is determined by the induced power loss, is also a function of the frequency. In the individual data sheets, the ripple current capability of the capacitors is generally referred to a frequency of 100 Hz or 120 Hz. Depending on the main applications, other frequencies are also possible."[1]
"Capacitance is measured under standard conditions to IEC 60068-1:2013. In case of doubt, stricter reference conditions are defined in sub-clause 5.2 of the same specification.
"The generic standards and the sectional standards specify the same measuring conditions for dissipation factor tan δ as for capacitance (refer to chapter 2.2.1). 1 kHz is the standard measuring frequency. For MKT, MFP and MKP film capacitors with C_R ≤1 μF, additional measuring frequencies of 10 kHz or 100 kHz are used to determine the dissipation factor."[2]
Sources:
[1] TDK Electronics AG. Aluminum Electrolytic Capacitors. General technical information.
[2] TDK Electronics AG. Film Capacitors. General technical information.
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That is the second one I bought as well.
DonR
Major Contributor
0.5v is also great for in-circuit measurement as it doesn't turn on most PN junctions. Peak Atlas uses less than 0.1V
I use a Keysight E5061B with the LF+impedance analysis option. It's a nice instrument. It's my employer's so cost was not really a factor. I will say that it beats the pants off an LCR meter in accuracy, precision and overall usefulness.
But yeah, not many hobbyists are going to drop the.... $45k for that instrument and the cal standards.
But yeah, not many hobbyists are going to drop the.... $45k for that instrument and the cal standards.
For capacitor value etc. measurements I have DER-EE DE-5000.
For on-circuit measurements and fault finding I have ESR-Micro V4.0S and ESR-Micro V5.0S. Those ESR-Micro meters are awesome and V5 is protected against DC voltage up to 300V (charged capacitor...).
For on-circuit measurements and fault finding I have ESR-Micro V4.0S and ESR-Micro V5.0S. Those ESR-Micro meters are awesome and V5 is protected against DC voltage up to 300V (charged capacitor...).
antennaguru
Senior Member
That's a good point! I always discharge any capacitor I am going to measure, or work on, FIRST.
A charged cap could fry your LCR meter, or give you a wake up call you won't forget. I have been amazed how some caps can hold a charge for weeks. Always discharge through a resistor as a current limit so you don't damage your metal tools. I use a big wirewound 1K resistor for discharging.
When I build supplies I always build in a bleeder resistor.
With lowish voltage circuits it's easy to forget to discharge capacitors first, but it doesn't take much to damage some meters...
With power supplies I always check capacitor voltages first, sometimes the circuit may have blown a fuse or a fusable resistor and the main filter capacitor still has almost full rectified voltage (250-280V over here).
And even after you discharge, voltage may still slowly creep up afterwards. The same care should also be taken with power amp filter capacitors. Voltage could also cause circuit damage if you measure some components (e.g. ICs or transistors) and shortcircuit component pins without realising that there still was some voltage in the circuit.
