As a result of me giving a webinar about Getting Started with Raspberry Pi and Accessories for element14, I was rewarded with a gift voucher which allowed me to purchase some much-desired equipment from element14. I decided that it would be nice to have an LCR meter, a relatively basic piece of equipment for any Electrical Engineer, however not one which many people own (probably because it’s not built into any old multimeter).
I had settled on the Agilent Technologies U1733C Handheld LCR Meter, listed at AU$421. It is part of a series of 20,000 count display handheld meters, namely the U1731C, U1732C and U1733C that predominantly differ in the test frequencies available. It’s definitely a quality piece of equipment, from a big name vendor.
The U1733C offers basic accuracy of 0.2%, selectable test frequencies of 100Hz, 120Hz and 1kHz, 10kHz and 100kHz. It features auto component identification, auto-ranging, battery operation for up to 16 hours and optional infrared connectivity. It can also make measurements of DC Resistance, Equivalent Series Resistance, Phase Angle, Q factor, Dissipation Factor. It has a three year warranty, and a one-year calibration cycle.
It’s probably not easy for hobbyists to decide to part with even that amount of money for test equipment, but as I’ve done a boatload of capacitor swaps due to the capacitor plague, it’s been a bugbear of mine that I have had no equipment to measure capacitance or ESR, some very basic metrics which can tell you if a capacitor is any good.
This is a very quick review of what I think about the U1733C.
The Product and Impressions
As usual, element14 were unbelievably prompt in delivering the product, as it was in stock.
It comes in a sturdy box, which lists all of the important product features. It seems all of the meters from this series come in the same box.
Inside, there is a box contents list which clearly states what items are included. This includes the unit itself, a set of short test clip leads, a battery, quick start guide, calibration certificate, and some regulatory leaflets.
Something I didn’t expect was this piece of informative material which lets us know that Agilent Technologies Measurement Group will become known as Keysight Technologies.
So many name changes! I’m sure some readers will remember them as Hewlett Packard.
Supplied is a small quick start guide, although downloading the full manual from Agilent’s web site is advisable. Many of the menu configuration options – e.g. calibrating for your test leads at every frequency and range, selecting the start-up measurement mode and nulling data, changing the automatic power-off features are only available from the menu detailed in the full manual.
There is a full calibration certificate as well, as expected from serious quality equipment.
The unit itself is in the familiar Agilent orange, and feels solid and chunky in the hand. It doesn’t creak when held in the hand. The front is relatively sparse with only an array of rubbery push-buttons, but to its credit, it has a very large LCD display with backlight.
Most buttons control more than one feature depending on long or short press durations. This is clearly printed on the unit itself, and is easy to get to grips with. The auto-ranging seems to work well, as well as the auto-identification which selects the most appropriate measurement mode based on the phase angle measurement (Z, L, C, R).
With the springy slots available above the banana clips, it’s easy to test leaded components by inserting them straight in. How convenient!
Use of the clips is more practical in other instances, and they can be nulled using the calibration feature and stored into the User preset, allowing for precision measurements of low resistances, capacitances and inductances. In fact, it’s much better over a wide range of resistances, that I no longer use my low-cost multimeters to measure resistance – how naive of me to think that the regular multimeters were “decent”.
It does allow for data logging and interfacing to a PC, however, it’s only via their special infrared adapter. That’s a bit of a disappointment that they didn’t opt for a more standards method of connectivity.
The unit does have an external 12v DC barrel input for continuous use, and a sturdy flip-out kickstand. The battery is inserted under a screw-down cover underneath the kickstand.
Sorry folks. I’m not going to do a teardown of this one … because one of my favourite people has already done it!
So, why is it useful? Well, in the case of capacitor plague, you might not know if the capacitors you’ve salvaged are any good. One indication of its quality is the capacitance itself, and the other is equivalent series resistance (ESR). The ESR figure is the series resistance with the capacitor which determines the amount of energy and heat dissipated, especially with high ripple currents, and generally how effective a capacitor is at smoothing fast variations. Unfortunately, the ESR value isn’t widely publicised and guideline values aren’t easily available making interpretation a little difficult. It’s mainly of concern for electrolytic capacitors used in high ripple situations (e.g. switchmode power supplies).
You can see the first capacitor measures just above 2.2uF at 100Hz, but it has a dissipation factor of 0.039, phase angle of -87.7 degrees, and an ESR of 27.53 ohms. The second capacitor has less capacitance at 1.9882uF at 100Hz, but a better dissipation factor of 0.30, phase angle of -88.2 degrees and ESR of 24.56 ohms. You can see the auto-ranging making the required decisions to maximise the use of the range, and the use of the user null presets which I had pre-calibrated the leads for. Manual ranging is accommodated for, but requires a few pushes of the buttons to toggle between ranges.
The three section battery indicator can also be seen, as well as the activation of the orange backlight which provides very good contrast.
What’s a good ESR? It’s hard to tell, but some fresh 2200uF Matsushita/Panasonic capacitors measured a tiny 0.0623 ohms!
Many can measure below 1 ohm, whereas others like to measure in the tens of ohms. The higher the resistance, the poorer its performance will be to high ripple current situations in terms of efficiency, response, and heat generation, which also affects lifetime.
Lets try a mystery inductor …
It’s nice also to use the DC resistance measurement to get an idea of the copper winding resistance …
… or you can put it into the resistance mode just to measure the impedance of a resistor. Given the phase angle, we’re pretty sure it’s a resistor, but given it was a 0.18 ohm resistor with 5% tolerance, this measurement is spot on and is something most handheld multimeters would struggle with.
Toggling between series and parallel mode measurements can easily be achieved by pressing and holding on a button. There is also the ability to invoke a memory mode, or to compare components to a particular tolerance value from a “golden sample” that had been measured and memorised prior.
If only the tolerance mode instead displayed the nearest E12 value with a percentage from that value, as that would help component sorting. It’s a little annoying the product’s automatic power off involves beeping, and keypresses involve beeping as well, but that’s a common issue amongst test equipment. It’s a minor thing.
It’s a handheld LCR meter – it’s not glamorous but it feels solid, and it does what it says on the box. It’s relatively easy to use, it’s got a good display and its pretty accurate for a piece of handheld kit. It does measure almost everything you’d expect an LCR meter to do, but it is a shame that the IR interface is proprietary, so you cannot just use any IR dongle and terminal software with it. It definitely makes my life easier when sorting out salvaged capacitors and mystery inductors! It’s been a delight to own and use. Thanks a lot for this, element14!