Well i decided to buy a newer multimeter for my electronics works and so will use this mainly around up to 50V AC/DC: Got it delivered yesterday from conrad: It is on sale here right now in sweden and is on sale for like 50€ so i know it might not be the best quality like fluke, appa and gossen and so on was a bit curious on how the inside of this meter looked like so i took it apart and took some photos of it. The feeling of the multimeter otherwise in quality feels pretty solid it got 4 screws holding it together and the input jacks are pretty solid compared to uni-t ut61x series where there is a flimsy little metal tube pushed down in the front and held down by the back cover it also warn you of cables in the wrong terminals too, me i find it pretty ok even if i know well enough not to use the wrong inputs and so. I have looked at the construction and i like it pretty much seems to have both ptc and movs and a bunch of serial resistors on the input 3 x 33m? And 4 x 2.5m? Before the input of the ic seems pretty ok and after i saw the other side of the pcb i am pretty happy with this unit. So updated the post with more images of both sides of the pcb, and i changed the thread name as it became a teardown lol. I bought this meter about 2 years ago, also for €49,99 (special offer).

I was planning to post a teardown of it here (already made the photos), but never got around to it and Hagis2k beat me to it. Considering the rather poor accuracy specs I doubt that UNI-T went to much trouble calibrating/adjusting this meter. Unless you get any response from Conrad or UNI-T (I wouldn't hold my breath until that happens), probably your best bet would be the datasheet I linked here before and a bit of reverse engineering to figure out what the pots in this meter do. Before you start playing with these you better have access to some kind of reference that is significantly more accurate than the stated accuracy of your meter. Anyway I wonder why you care. The VC-850 is simply not a precision instrument and it is not going to be no matter what you do with it. For many purposes its accuracy is good enough, but if you need really accurate measurements this is the wrong meter.

Voltcraft VC960 - V06-09 Pdf User Manuals. View online or download Voltcraft VC960 - V06-09 Operating Instructions Manual. Voltcraft Vc 960 Software Testing. A VC-960 Multimeter by Voltcraft served as. While we found this software. Voltcraft VC 960 Battery RuntimeThe battery.

Compared to my Fluke 179 (stated DC volts accuracy: 0.09%+2 digits, which is average at best but still a lot better than the VC-850), I noticed that the divergence is not uniform across the voltage range. At some voltages the indication on the VC-850 is a few counts higher than on the Fluke 179, at other voltages it is a few counts lower, and at some voltages they pretty much agree. A simple adjustment won't make those all go away.

Received 22nd November 2016, Accepted 31st December 2016 First published on 17th January 2017 Multilayer inkjet printing is emerging as a robust platform for fabricating flexible electronic devices over a large area. Here, we report a straightforward, scalable and inexpensive method for printing multilayer three-dimensional nanoporous redox cycling devices with a tunable nanometer gap for electrochemical sensing. The fabrication of the electrochemical redox cycling device is based on vertical stacking of two conductive electrodes made of carbon and gold nanoparticle inks. In this configuration, the two electrodes are parallel to each other and electrically separated by a layer of polystyrene nanospheres.

As the top and the bottom electrodes are biased to, respectively, oxidizing and reducing potentials, repetitive cycling of redox molecules between them generates a large current amplification. We show that a vertical interelectrode spacing down to several hundred nanometers with high precision using inkjet printing is possible. The printed sensors demonstrate excellent performance in electrochemical sensing of ferrocene dimethanol as a redox-active probe. A collection efficiency of 100% and current amplification up to 30-fold could be obtained. Our method provides a low cost and versatile means for sensitive electrochemical measurements eliminating the need for sophisticated fabrication methods, which could prove useful for sensitive point-of-care diagnostics devices.

Introduction Redox cycling at the nanoscale is a highly sensitive method for electrochemical detection of redox-active analytes. The method relies on amplification of Faradic currents due to recurrent oxidation and reduction of redox-active molecules between two closely spaced and independently biased electrodes.

The amplified current provides quantitative information on the concentration of the redox-active molecules allowing direct detection of analytes at low concentrations. The distance between the two electrodes plays a significant role here, as the amplified current inversely scales with the interelectrode distance. Recently, the Lemay group has demonstrated single-molecule resolution, the ultimate level of detection, using microfabricated nanofluidic redox cycling devices. Since the introduction of redox cycling devices in electrochemistry, a variety of electrode configurations has been studied. Apart from probe-based techniques, such as scanning electrochemical microscopy, most investigations have been performed using interdigitated electrodes (IDE) with a narrow interelectrode distance. Simple Port Forwarding Serial Number. However, the minimal distance between the anode and the cathode is limited by the lateral resolution of the fabrication process.

Thus, advanced lithographic techniques are required to fabricate efficient redox cycling devices at the nanoscale using IDE configuration. An alternative to the lateral configuration is a multi-layer vertical electrode arrangement. Here, two electrodes are aligned on top of each other and are separated by a thin sacrificial layer, which is etched away in a post-processing step to form a nanogap. In this configuration, the thickness of the sacrificial layer will determine the distance between the two electrodes.

Conceptually, this design has the advantage of allowing the realization of a defined gap between the electrodes down to the nanometer range. Another interesting approach is redox cycling in nanoporous devices. These sensors are based on metal/insulator/metal stack with pores created on the top electrode and the insulator layer allowing the diffusion of analyte solution to the bottom electrode through the pores offering a high temporal resolution for electrokinetic studies. Yet, all of the aforementioned designs utilize rather expensive state-of-the-art microfabrication techniques. If redox cycling devices are going to be applied in areas requiring low cost of production, such as point-of-care testing, alternative fabrication methods have to be considered.

Recently, Park et al. Have demonstrated a bench-top fabrication of a redox cycling sensor of vertically stacked electrodes using 0.54 to 8 μm beads as a spacer.

However, their method involves several substrate treatment steps and most importantly a manual assembly of two separated electrode plates, which is a very tedious and time-consuming, and therefore, an unscalable procedure. On the other hand, additive manufacturing methods such as inkjet printing offer a practical solution to cost and scalability problems. Although lateral resolution in ink-jet printing is limited by the smallest drop size to approximately 10–20 μm, if Z resolution of inkjet printing is exploited, vertical interelectrode spacing down to several hundred nanometers is feasible. Here, for the first time, we present an array of fully printed three-dimensional redox cycling sensors using multiple functional inks. Neither substrate pre-treatment nor post-possessing beyond sintering were used during fabrication since the inks inherently possessed all the required functionality. We used inkjet printing for fabricating a vertically stacked redox cycling device using carbon and gold nanoparticle inks.

Each printed chip has material costs of less than 5 cents (see Table S1). At the same time, we combined a novel nanoporous material made of layers of polystyrene nanospheres for electrical isolation between the two electrodes.

As schematically illustrated in, the redox cycling device consists of a porous top carbon electrode, which allows the transport of the electrolyte solution to the bottom electrode. The bottom electrode (made either of gold or carbon nanoparticle inks) is separated by a nanoporous layer, thereby allowing the diffusion of redox molecules between the two electrodes. The entire device was passivated with a dielectric ink as described in the experimental section, leaving only the sensor area (three layer system described above) exposed to the electrolyte. 1 (a) The principle of redox cycling in a nanoporous device: reduced species (blue circles) is first oxidized at the top electrode (red circles) and then diffuses through the pores of the polystyrene layer to be re-reduced at the bottom electrode (blue circles). Thereafter, the process is repeated until the molecule escapes the device. (b) Schematic illustration of the fabrication flow of the redox cycling sensor. (c) Cross-sectional SEM image of the printed device (d) the measured cyclic voltammograms recorded at the carbon top electrode (black curve) and at the bottom gold electrode (red curve) with 500 μM Fc(MeOH) 2.

The potential of the bottom electrode was held at 0.0 V while the top electrode was swept from 0.0 V to 0.6 V at a scan rate of 20 mV s −1. We performed a proof-of-principle demonstration of a redox cycling device using a gold nanoparticle ink as a bottom electrode material. Further experiments were carried out using carbon bottom and top electrodes instead of gold for three key reasons: (a) carbon is a cheaper alternative to noble metals; (b) the use of carbon in electrochemistry has been and continues to be of great interest across a wide range of applications due to its wider potential window compared to gold (see Fig. S1); (c) the use of carbon-based materials in cleanroom technology still poses a technical challenge, although carbon electrodes are ubiquitous in cutting-edge platforms such as supercapacitors, fuel cells, and bioelectronics. The results presented here involve the use of printed microelectrodes (ME) as the sensing electrode. As opposed to macroelectrodes, ME feature a three-dimensional diffusion field, which leads to a steady-state current, and faster electron transfer due to smaller size and lower capacitance values, which in turn leads to enhanced sensitivity.

Microelectrode array systems have been reported in literature for the single-molecule detection and single-molecule electrocatalysis owing to their inherent advantages. Results and discussion Printing process The printing process is shown in. Silver nanoparticle ink was first deposited on a polyethylene naphthalate (PEN) substrate forming the feedlines for electrical connections followed by either a gold or carbon ink deposition for the active bottom electrode. Both inks were prepared as described in the experimental section.

Afterward, a dielectric polyimide ink was used to passivate the electrodes and define an electrode opening as shown on the microscopic image of the fabrication sequence in Fig. As a next step, a polystyrene nanosphere ink was printed onto the bottom electrode. This layer was crucial in providing mechanical stability to the next deposited layer. Upon drying of the polystyrene nanosphere layer, a carbon top electrode was printed on top of it. Finally, the entire sensor was cured using photonic sintering to sinter the upper carbon layer without damaging the polystyrene nanospheres. An additional potential advantage of using a polystyrene nanosphere ink is the possibility to later utilize carboxyl or amine functionalization to bind a biorecognition element such as DNA or protein for sensing applications. Another feature of this approach, namely using a nanoporous dielectric layer, is the elimination of the sacrificial layer and with it of the post-etching step, which is typical in the fabrication of two superimposed electrodes.

Shows a cross-sectional view obtained from Focused Ion Beam (FIB) milling of the device. Approximately 280 nm separation between the top and the bottom electrodes can be observed as three layers of polystyrene nanospheres were printed. This demonstrates the ability to print a multilayer stack of four different material inks with high precision. Demonstrates successful utilization of the fabricated device for sensing of ferrocene dimethanol as a redox-active probe. Here, the top anode is providing the oxidizing potential to the redox molecules as it is being swept from negative to positive potentials, while the bottom cathode collects and reduces all the molecules that have been previously oxidized at the top anode and diffused to the cathode. This is evident from the collection efficiency that is close to 100% in our device. The collection efficiency η is defined by the ratio of the current for reduced species at the bottom electrode divided by the current for the oxidation of reduced species at the top electrode, see.

(1) A camera image of the fabricated redox cycling chip is shown in. Each chip consists of 25 sensors (50 feedlines) printed using silver and carbon inks on PEN substrates. The width and length of each bottom carbon electrode were 45 μm and 60 μm, respectively, as seen in. The top electrodes were arranged above the bottom electrode having a width of ∼220 μm and a length of ∼145 μm. The complete fabrication steps are depicted in the ESI.

The repeatability of the process in lateral resolution is in the range of 4%. Shows the nanoporous layer of as-printed polystyrene nanospheres. The surface morphology and the porosity of the printed carbon electrode are evident from the high magnification SEM image in. 2 Large scale inkjet printing of vertically stacked redox cycling sensors: (a) optical image of inkjet-printed redox cycling device on a flexible substrate.

(b) Microscopic image of a printed carbon electrode (c) and (d) SEM images of printed polystyrene nanospheres and carbon, respectively. The thickness of the polystyrene film critically depends on the number of printed layers. Although a small distance of 200 nm between the top and the bottom electrodes was possible as seen in, we printed arrays of redox cycling sensors with a 1200 nm distance. We did that in order to increase the yield of functional devices by avoiding possible failures due to short circuits and to ensure higher mechanical stability of the top carbon electrode.

This larger distance between the two electrodes was achieved by printing 12 layers of polystyrene nanospheres. Consequently, this interelectrode distance d defines the amplification.

It should be noted that the redox cycling current scales with 1/ d for vertical gap devices. In the case of a nanoporous gap, additional obstacles to the diffusion of redox molecules are introduced. Therefore, we further characterized the sensors as shown in the electrochemical results in using an all-carbon printed device. To test the sensitivity of our devices, we constructed an electrochemical calibration curve with varying concentrations of ferrocene dimethanol as shown in part (a) and (b) of.

Shows the dependence of the oxidation current at the top electrode on the concentration of the redox molecules. The response was linear ( R 2 = 0.98) over a range of 250 μM to 1 μM for the top electrode, as shown in.