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The measuring laboratory that we use to perform our tests is funded by the donations we have received from you. On this page, we provide an overview of the equipment we have purchased with these donations. |
Introduction
Universal testing requires a lot of measuring equipment
We want to be able to thoroughly test all kinds of equipment that electronics hobbyists bring into their homes. This requires a lot of equipment, which is sometimes only used rarely for a single specific test, such as a harmonic distortion measurement. Often, this equipment is also quite expensive. After all, in order to test a multimeter with a specified accuracy of ±0.1 %, a reference meter with at least ten times better accuracy, i.e. ±0.01 %, is required. The bandwidth of a modern hobby oscilloscope goes up to 100 MHz and to evaluate this, an RF-generator is needed that delivers sine waves up to at least 200 MHz with a guaranteed constant amplitude over the entire frequency range.
We can only measure the distortion of modern LF amplifiers if an LF-generator is available that delivers a sine wave with the lowest possible distortion, preferably less than 0.05 %. In addition, a sharp-cutting bandpass filter is required to remove the measurement frequency from the output signal of the amplifier under test. This allows us to measure the harmonic distortion that the amplifier adds to the input signal.
In order to be able to carry out all these measurements properly, we have been able to set up the test laboratory below over the seven years that this blog exists. And this, of course, thanks to your generous donations and gifts! A detailed overview of the donations we receive can be found on:
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| An overview of our measuring equipment. (© 2025 Jos Verstraten) |
Costly renewal necessary!
This laboratory has not been in existence for very long, approximately seven years. Nevertheless, renewal is necessary. This is due to the fact that inexpensive measuring equipment, mainly from China, is constantly improving. An example: ten years ago, a hobbyist would have been extremely satisfied with a multimeter with a count range of 1999. To test the accuracy of such a meter, a multimeter with a count range of 19999 (and corresponding accuracy) was sufficient. Now, multimeters with a count range of 25000 and a specified accuracy for DC voltage of ±[0.05 % + 3] are available for around € 35.00. To test such a device, a multimeter with a count range of 199999 and an accuracy that only professional equipment can offer, such as ±[0.006 % + 3], is required. Purchasing such meters is quite expensive!
So... please continue to support us generously with donations; your contributions are well spent!
This article may also be of interest to you
We did not purchase the selected devices on a whim, but after a thorough analysis of what is available on the market and the price/performance ratio of various devices. So perhaps you can make use of our extensive market research if you want to expand your own lab with certain equipment.
Our power supplies
Two power supplies TPS305 from WANPTEK
These power supplies deliver DC voltages up to 31 V at currents up to 5.2 A. They are inexpensive unpretentious hobby power supplies, but good enough for the purpose for which we use them: powering the electronics kits we build and test. We have, of course, tested this power supply:
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| The TPS305 power supply from WANPTEK. (© 2024 Jos Verstraten) |
Power supply 12 V ~ 30 A
In order to test low voltage DIY kits that require a lot of power, such as Tesla generators and induction heaters, we built our own 12 V power supply that can be loaded up to 30 A. We came up with the brand name 'Verelon', which stands for 'Verstraten elektronica ontwerp' (Dutch for 'Verstraten electronics design'). Even DIY devices can look professional!
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| Our 12 V at 30 A power supply. (© 2025 Jos Verstraten) |
High-voltage power supply from Emeco
Most multimeters have a DC voltage measurement range of 600 V or sometimes even 1 kV. In order to assess the accuracy of this range, we obviously need a DC voltage of 1,000 V. After a long search on the internet, we found a device that is inexpensive and delivers such voltages: the Emeco breakdown voltage tester. This meter is intended for testing the breakdown voltage of semiconductors up to a maximum of 2,700 V, but it is also excellent for supplying a DC voltage of 1,000 V to a multimeter. You can read a review of this device at:
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| The Emeco high-voltage power supply. (© Banggood) |
Variac up to 300 V
A variac, an adjustable transformer, is essential for testing the input stability of power supplies. By varying the mains voltage of the power supply via the variac, we can precisely determine the limits within which the power supply generates a stable output voltage at maximum load.
Such a device is also useful for checking the accuracy of multimeters when measuring AC voltages between 20 V and 300 V. For measurements below 20 V, we can of course use our function generator. We have purchased one that reaches just 300 Vac when the mains voltage is a little on the high side.
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| A variac, indispensable in any test lab. (© Weltechniek) |
An isolation transformer
Equally indispensable in any electronics laboratory to guarantee the physical safety of testers and expensive equipment. An isolation transformer ensures complete separation between the phase and neutral of the mains voltage and the circuit or equipment being tested. If you use an isolation transformer, you can never get an electric shock if you touch a point in a circuit with only one finger. Keep the other hand on your back! This is because the isolation transformer ensures that there is no closed circuit between that point and the earth that your feet are in contact with. This means that no current can flow through your body. We built one in a little box, so that even something as ugly as an isolation transformer looks nice.
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| The indispensable isolation transformer. (© 2019 Jos Verstraten) |
Our measuring equipment
What needs to be measured?
In an electronics measuring laboratory, a large number of quantities need to be measured:
- Voltage DC or AC in volt (mV ~ V)
- Current DC or AC in ampère (μA ~ mA ~ A)
- Resistance in ohm (Ω ~ kΩ ~ MΩ)
- Capacitance in farad (pF ~ nF ~ μF ~ mF)
- Inductance in henrie (μH ~ mH ~ H)
- Temperature in degree Celsius (°C)
- Frequencie in hertz (Hz ~ kHz ~ MHz)
- Voltage gain in bell (dB)
- Current gain in a dimensionless number
- Signal distortion in percent (%)
This cannot be done with a single measuring device!
The multimeter 8842A from Fluke
This is undoubtedly the jewel in the crown of our measurement lab. The 8842A is a digital precision multimeter that Fluke produced in the 1980s and 1990s. It is still a highly valued instrument in laboratories due to its high accuracy and stability. It has a resolution of 5.5 digits, giving a readout of up to 199999. For DC voltages, it has an accuracy of ±0.003 % of the reading. The 8842A is famous for its long-term stability and reliability. Many units from the 1980s still function within specifications today. Our unit was calibrated in 2020 and was found to be working fully within specifications. However, we have a model without rectifier extension, so we can only use this meter for accurately measuring DC voltages, DC currents and resistances.
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| The Fluke 8842A multimeter. (© 2020 Jos Verstraten) |
The multimeter ET3255 from EastTester
This is our second digital multimeter, this time from China. It has a count range of no less than 240,000. We purchased it because we also wanted to measure AC voltages with high accuracy. This meter proves that Chinese manufacturers have mastered the art of making accurate multimeters.
According to the specifications, it has an accuracy of ±[0.01% + 3] for DC voltage. However, when we connect the ET3255 and the 8842A in parallel to a DC voltage, the E3255 deviates only a few digits from the reading on the Fluke. The same applies when measuring resistances. For AC voltages, an accuracy of ±[0.2% + 100] is specified, which is good enough for testing the inexpensive hobby meters we discuss on this blog. Importantly, AC voltages are measured between 20 Hz and 100 kHz, a range that few digital multimeters in this price range can match.
The ET3255 is a true multimeter: in addition to A, V and Ω, you can also measure capacitors, frequencies (up to 20 MHz!), temperatures and dB's.
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| The ET3255 from EastTester. (© EastTester) |
The multimeter Model 8 MK3 from AVO
Like all electronics engineers of a certain age, we grew up with this analogue universal meter. However, our continued fondness for it is not solely based on nostalgia. An analogue meter with a needle is ideal for adjusting a voltage or current to a minimum or maximum value. No modern digital multimeter can match this, even if it is equipped with a thermometer scale as second display, which by definition has a resolution that is far too low!
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| Model 8 MK3 from AVO. (© Peter Vis) |
The mVac meter PM2454B from Philips
We use this analogue AC millivolt meter to measure, for example, the average value of the noise and ripple voltage at the output of a power supply that is being tested. With its minimum full-scale range of 1 mV, we can even put the best power supplies through their paces in this respect. We also often use this meter when measuring amplifiers and LF generators. Thanks to its frequency range of 12 MHz, it is also possible to accurately measure the constancy of the output voltage of low-cost function generators.
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| The Philips PM2454B millivolt meter. (© 2025 Jos Verstraten) |
The LCR-meter ET4401 from EastTester
Now that virtually all digital multimeters are capable of measuring capacitors, a measurement laboratory needs to have a reliable LCR-meter. The DE-5000 from DER-EE is often considered the best choice. We followed our own path and ended up with the ET4401 from EastTester. The DE-5000 is a hand-held model, which we are not particularly fond of. The ET4401 is a robust bench-top meter that comes standard with a Kelvin probe consisting of four shielded coaxial cables. This LCR-meter has a basic accuracy of 0.2 % and measures with six AC voltage levels with a frequency that can be set between 100 Hz and 10 kHz. If desired, you can superimpose a DC voltage on this measurement signal to ensure that electrolytic capacitors remain properly polarised. Our model appears to measure our standard capacitors with a minimal error, better than the specified 0.2 %:
- 1 μF ~ ±0.05 % ➡ 1.0013 μF
- 100 nF ~ ±0.05 % ➡ 100.01 nF
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| The ET4401 LCR-meter from EastTester. (© Banggood) |
The frequency meter PM6669 from Fluke
We measure the frequency accuracy of generators with this small and handy frequency meter. Its range of 160 MHz is large enough to check all the generators we test. With a resolution of nine digits and an internal crystal oscillator deviation of less than 1.2 × 10⁻⁵, this meter currently meets our requirements.
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| The Fluke PM6669 frequency meter. (© Fluke) |
The distortion meter HM8027 from Hameg
We use this self-tuning digital harmonic distortion meter to check the harmonic distortion of function generators and LF-amplifiers. The frequency range is from 20 Hz to 20 kHz, divided into three ranges. Distortion is measured in two ranges of 100 % and 10 %, with a minimum measurable value of 0.01 %. The own distortion is very low, typically 0.005 % at 1 kHz. The BNC output gives the residual signal (the distortion), which can be made visible on an oscilloscope.
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| The HM8027 distortion meter from Hameg. (© Hameg) |
The temperature meter model 52 from Fluke
All modern multimeters also measure temperatures, so a reference °C meter is a must-have in any well-equipped measurement lab. We found Fluke's model 52, a digital temperature meter that has two inputs for type J, K, T or E thermocouples. Depending on the type of thermocouple used, the measuring range is from -210 °C to +1,372 °C. The accuracy of the meter is ±[0.05 % + 0.3 °C] above -100 °C. Please note that you must add the accuracy of the thermocouple used to this!
We also use this meter to measure, for example, the heating of the output transistors in power supplies at maximum load.
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| The Fluke model 52 temperature meter. (© Fluke) |
The semiconductor tester TT100 from Voltcraft
This device, which is unfortunately no longer available, was a competitor to the well-known DCA55 semiconductor tester from Peak Electronic Design. It was considerably cheaper and could do much the same thing, measure the main specifications of semiconductors:
- Forward voltage of diodes and LEDs.
- Current gain of bipolar transistors.
- Base/emitter-voltage of bipolar transistors.
- Collector leakage current of bipolar transistors.
- Any shunt resistance between B and E of bipolar transistors.
- Threshold gate voltage of MOSFETs.
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| The TT100 semiconductor tester from Voltcraft. (© 2020 Jos Verstraten) |
The temperature logger EL-USB-TC from Lascar Electronics
Sometimes we want to record the change in temperature over time, for example, the heating of the output transistors of a linear power supply or the temperature change at the tip of a soldering iron when soldering several joints in quick succession. For this, we use an EL-USB-TC from Lascar Electronics. This works with a thermocouple probe and can store up to 32,000 measurements in its internal memory. The measurement interval is adjustable between one second and twelve hours. The data can be transferred via USB to a Windows PC and processed in a graph.
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| The EL-USB-TC logger from Lascar Electronics. (© Lascar Electronics) |
Our oscilloscope
The XDS2102A from Owon
We started our test laboratory with a simple eight bit oscilloscope, the DSO5102P from Hantec. However, being used to working with analogue oscilloscopes with their beautifully smooth image, we became increasingly irritated by the low resolution of eight bits. It was as if rats had gnawed at the traces!
In August 2021, a twelve bit oscilloscope (expensive for our budget) was purchased: the XDS2102A from Owon. What a relief, that four bit difference in image quality!
The specifications of this device in brief:
- Bandwidth: 2 x 100 MHz (not Chinese 100 MHz, but real!)
- Sample rate: 1 GSa/s
- Resolution: 12 or 8 bits
- Memory depth: 20 MPts
- Waveform capture rate: 55,000 Wfm/s
- Horizontal scale: 2 ns/div ~ 1,000 s/div
- Vertical scale: 1 mV/div ~ 10 V/div
- Rise time: ≤ 3.5 ns
Although we dream of one day being able to switch to a 300 MHz oscilloscope, as the hobby devices we test are becoming increasingly broadband, we are currently very satisfied with this 100 MHz viewing box.
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| The XDS2102A oscilloscope from Owon. (© Eleshop) |
Our signal generators
The function generator DG1022 from Rigol
Thanks to your donations, we have also made great advances in terms of the main signal source in a laboratory: the function generator. We started with a second-hand analogue IFG-422 from Intron, then moved on to an FY3200S from Feeltec, followed by a UTG9005C-II from UNI-T and finally a DG1022 from Rigol.
The maximum output frequency of this device is 20 MHz for sine waves and 5 MHz for other waveforms. The sample rate is 100 MSa/s and the signal shapes of the first channel are composed with a resolution of 14 bits. What we particularly like about this generator is that the device can be set to a specific output signal very quickly using the keypad.
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| The DG1022 function generator from Rigol. (© Eleshop) |
The HF-generator TF2015 from Marconi
To test the bandwidth of an oscilloscope, a sine wave generator is required that delivers signals with a frequency of at least 200 MHz with a guaranteed constant amplitude, regardless of the frequency. We have found such a device, the TF2015 from Marconi. The TF2015 covers frequencies from 10 MHz to 520 MHz, divided over 11 switchable bands. Each band has its own scale on a rotating cylinder. A very ingenious mechanism is linked to the range switch and rotates the correct scale for the window in the front panel. You don't see anything like this anymore! An 'ALC' (Automatic Level Control) ensures a very stable output amplitude for all frequencies. The maximum deviation is only 1 dB up to 100 MHz and 2 dB up to 200 MHz. The output voltage is adjustable between 0.2 µV and 200 mV, and extensive shielding prevents the output voltage from leaking through the housing or the power cord.
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The TF2015 HF-generator from Marconi. (© 2025 Jos Verstraten) |
The LF-generator PM5109S from Philips
For measurements on audio amplifiers, we need a generator that delivers clean, distortion-free sine waves. With a maximum harmonic distortion of only 0.03 % between 300 Hz and 20 kHz and 0.07 % between 10 Hz and 100 kHz, this analogue RC-generator meets this requirement. The frequency range is from 10 Hz to 100 kHz, divided into four sub-ranges via push buttons. It has a calibrated dB attenuator of 10 dB, 20 dB and 30 dB, allowing the output signal level to be set very accurately. The built-in meter has a full-scale range from 10 V to 10 mV. Measuring an amplitude/frequency characteristic is a piece of cake with this device.
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| The PM5109S LF-generator from Philips. (© 2025 Jos Verstraten) |
The LF-generator HM8037 from Hameg
One of our latest acquisitions is this slightly more modern analogue RC-generator from Hameg. It is designed to work in conjunction with the HM8027 distortion meter discussed above. It has a frequency range of 5 Hz to 50 kHz. The harmonic distortion is typically around 0.005 % at 1 kHz and a maximum of 0.05 % at 50 kHz. The amplitude deviation is given as a maximum of ±0.2 dB over the entire frequency range.
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| The HM8037 LF-generator from Hameg. (© Hameg) |
The pulse generator PM5712 from Philips
A fast pulse generator is essential for testing an oscilloscope. You can investigate how well the triggering works on single fast pulses, check rise times, etc. We opted for the Philips PM5712. It has a frequency range of 1 Hz to 50 MHz, rise and fall times of less than 4 ns, a pulse width of 10 ns to 100 ms and an amplitude of 0.2 V to 10 V at 50 Ω output impedance.
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| The Philips PM5712 pulse generator. (© SG-Labs) |
Our specialised equipment
The digital synchroniser TF2171 from Marconi
To test the accuracy of a frequency meter, you obviously need an HF-generator that delivers a very accurate frequency. We are the proud owners of a Marconi TF2171 digital synchroniser. This is an extension of the TF2015 HF-oscillator. The TF2171 has an extremely stable and accurate internal frequency standard of 5 MHz and a lot of digital frequency dividers, allowing you to set the frequency of the TF2171 to within 100 Hz using seven rotary switches.
Both devices are part of a feedback system that uses a PLL to match the frequency generated by the TF2015 to the frequency you set on the TF2171. This guarantees frequency accuracy and stability within typically [±1 × 10⁻⁶] (≈ 1 ppm).
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| The TF2171 synchroniser from Marconi. (© 2025 Jos Verstraten) |
The electronic load EBD-A20H from ZKE-Tech
This device allows us to load a power supply with a constant current between 100 mA and 20 A with a resolution of 10 mA. This enables us to measure and calculate the output stability, noise, ripple and dynamic resistance of the power supply. The maximum power that the EBD-A20H can continuously handle is 180 W. The maximum voltage that you can connect to the device is 30.0 V.
A review of this device has been published on this blog, read:
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| The EBD-A20H electronic load from ZKE-Tech. (© Banggood) |
The voltage reference AD584LH from Analog Devices
Every measurement laboratory must have a reference voltage for checking its own multimeters from time to time. We built this ourselves around an AD584LH from Analog Devices. The output voltage of this IC can be set to 2.500 V, 5.000 V, 7.500 V or 10.000 V. The deviation is typically ±2 mV with a drift of only 5 ppm/°C typical.
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| Our AD584LH voltage reference. (© 2019 Jos Verstraten) |
The digital microscope G1200(D) from Mustool
We use this to decipher the codes on the extremely small components that are found on all printed circuit boards nowadays. This microscope has an impressively large screen with a diagonal of 7 inches. The packaging and manual state that the G1200 magnifies up to 1,200 times. That is complete nonsense! The actual maximum magnification is a factor of 100, which is still impressive on the large screen.
You can read a review of this microscope on this blog:
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| The G1200(D) digital microscope from Mustool. (© Banggood) |
The fast edge pulse generator from Changsha Findra Trading
If we want to check the rise time of an oscilloscope, we need a pulse with a very short rise time. The shorter, the better! Our generators cannot deliver such pulses. That is why we have purchased a specialised little circuit board that generates a 1 MHz pulse with a rise time of only 180 ps. That is 0.180 ns, and when you consider that the rise times of the low- and mid-range oscilloscopes we test are around 3.0 ns, it is clear that this circuit board is ideal for this purpose. To prevent unwanted signal interference from cable reflections, you must plug this circuit board directly into the BNC connector of the oscilloscope to be tested.
Of course, we have discussed this handy tool on this blog:
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The fast edge pulse generator from Changsha Findra Trading. (© AliExpress) |
Our standard capacitors and resistors
Before we start testing a device, we check the functioning of our own measuring equipment. In addition to our voltage reference, we have also purchased a few highly accurate capacitors and resistors, known as 'standard' components.
The capacitors have a guaranteed tolerance of ±0.05 % and values of 0.1 μF and 1.0 μF. We also have a set of five standard resistors with a tolerance of ±0.01 % and an extremely low temperature coefficient. These components look like slightly oversized normal axial resistors, but they cost around twelve euros each!
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| Our two standard capacitors with a tolerance of ±0.05 %. (© 2025 Jos Verstraten) |
Our resistance decade boxes model 23022
Finally, here's a handy tip: two resistor decade boxes that we use, for example, to form a precisely adjustable potentiometer when we want to test at which reading an automatic multimeter switches to the higher range. The decade boxes we have are cheap Chinese junk, which we have upgraded, read:
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| One of our two resistance decade boxes. (© AliExpress) |
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