Features

The Hutale LCR-DDS-F 4.2 bridge meter kit is a multifunction device. The equipment is firstly a LCR meter (sometimes is called RLC meter or in other words LC meter, Ohm meter, in-circuit ESR meter) which precisely measures inductance, capacitance and resistance. The measurements can be carried out on 9 different, accurately made sine wave measuring frequencies (100Hz, 250Hz, 500Hz, 1kHz, 2.5kHz, 5kHz, 10kHz, 25kHz, 50kHz). Besides the main measuring parameters (inductance: Ls, Lp, capacitance: Cs, Cp, resistance: R) the secondary measuring features (impedance: Z, series resistance: Rs or ESR, reactive impedance: Xs, quality factor: Q, loss factor: D, phase angle) are measured too. The device is able to automatically choose the optimal measuring frequency and range to assure the optimal measuring conditions and best accuracy.
Besides these the device is a function generator that can produce 10Hz-100kHz sine, square, triangle and saw-tooth waves.
It can also function as frequency meter that measures frequencies between 3Hz-12.5MHz.

The 4.2 LCR-DDS-F meter kit is functioning base on one of the recently developed small voltage (<3.6V) AVR XMEGA microprocessor’s capabilities. A ready-to-use 4.2 LCR meter, function generator, frequency meter kit includes 1 pc. tested, calibrated meter assembled on a galvanized, 2-side, professionally made SMD PCB, 1 pc. tested LCD display, as well as 1 pc. 4 wire measuring cables with high quality Kelvin clips. The 4.2 LCR bridge meter kits are available.

I. Features of the LCR Bridge Meter

Measuring parameters:

Measuring ranges:

Basic accuracy: (Watch video, where precise components or well-known components by measuring them with factory LCR meter have been measured):

Measuring frequency:

Voltage of measuring signal:

Measuring technique: auto balancing bridge. Amperage and voltage are measured separately by using 4 wire (Kelvin) measuring cables

Measuring mode: series and parallel mode (ex. Cs, Ls is measured with series model, while Cp, Lp is with parallel model)

Impedance ranges:

Compensation, calibration:

Input protection: The 4.2 LCR meter is built with the PCB that has input protection that is based on a protection IC. This IC has low capacitance TVS diode arrays that are specially designed to protect sensitive components from overvoltage caused by electrostatic discharge (ESD), electrical fast transients (EFT), and lightning. It can bear a peak pulse power (tp=8/20µs) 300W, peak pulse current (tp=8/20µs) 12A, air voltage Vesd_air=15kV, contact voltage Vesd_contact=8kV

Measuring speed: 1 measurement / 3s

II. DDS function generator’s features

III. Frequency meter’s features

IV. Other features

V. About ESR measurement

Some mechanics are searching for ESR-meters so it is worth dealing with ESR measurement. In my previously developed (LCFesR) meter I used separated circuit so it was capable to measure ESR of electrolyte capacitor in-circuit. This was working nicely but it could not measure capacitor in-circuit. To measure capacity user must switch meter to capacitor-measuring mode and measure a capacitor standing alone (not in-circuit) - this is because of resonance measuring technique In this new-developed LCR-DDS-F meter these weaknesses are eliminated. In fact, an important innovation was introduced. This will be explained in details below.

Earlier we could read opinions that to determine the state of electrolyte capacitors we should use the ESR because it is more important than the knowledge of the capacity. This is generally true – there are lots of faulty capacitors with big ESR but their capacity seems not too bad. But there are cases where faulty capacitors have ESR value that seems OK. These can be caught with capacity measurement (capacity-reduction). So the state of a capacitor is determined the best way if we know both the ESR and capacity. ESR-meters have shortage: they only measure ESR and can’t measure capacity. There are simple capacity-meters that can’t measure ESR, neither in-circuit ESR. Users who use general LCR-meters experience that to get nominal value of electrolyte capacitors they must switch the test signal to 100Hz (at bigger frequencies capacity will reduce – the capacity at certain frequency is strongly frequency-dependent). However the ESR value measured at 100Hz is bigger than values in tables found on Internet or given by ESR-meters / capacitors manufactures, because these are measured at bigger frequency. So to get the capacity and comparable ESR value, general LCR-users (here it is worth mentioning that if a meter uses voltage with big amplitude then it can’t measure in-circuit ESR/capacity) have to take 2 measurements: first measure capacity at 100Hz, then manually switch to higher frequency to measure ESR. The Hutale LCR-DDS-F meter can do both the measurements automatically in one step. First it measures the capacity by using the optimal frequency, and then it immediately switches to 2.5kHz and measure the ESR (the difference of ESR value measured with 2.5kHz and with bigger frequency is not considerable, the ESR value measure at 2.5kHz is well useable) . If the ESR value <30Ω the meter displays that, else it displays the value measured with optimal frequency. With this new technique the LCR-DDS-F meter is a more comfortable to use instrument compared to other meters.

VI. Some thoughts

The Hutale LCR-DDS-F 4-2 LCR bridge meter, DDS function generator, frequency meter is a ready-to-use meter. To use it there is no need to use computer neither other device. We should know that the meter is working based on a modern measuring technique (auto balancing bridge) - the one big manufacturers use too. On Internet we can find some cheap meters that work base on simple techniques (resonance, only one square wave, measuring capacitor by charging / discharging it).  What can we expect from them? Less accuracy, less ranges, without input-protection, inconvenient to use (ex. we have to use switches that will wear out). There are a few factors that reveal these cheap meters: cheapness, few ICs on PCB or no details of PCB, simple 2-wire measuring cables, few information: no measuring technique, no frequency, no range or only few ranges, no preciseness, no input-protection, no video. So we should be aware of these when choosing a meter.

(More information about how the Meter is working, how to use it, etc. can be found in the documentation).