Most often, if modern electronic equipment fails, the blame electrolytic capacitors. Additional complexity in the search for broken capacitors arise from the fact that it is difficult to measure their capacity, since the capacity values in the defective capacitor can be almost the same as the value, but the ESR will be high. According to this, in this article we will discuss how to make the ESR meter with your hands.
Most often, it is due to high ESR values, proper operation of radio equipment may not be fully realized.
To facilitate the search for the faulty parts – we make manufacturing simple analog ESR meter. The device works on the following principle: check the resistance in the capacitor, when the frequency = 100 kHz. Capacitors, capacity of which exceed a few microfarads, will have a value approximately equal to EPS.
There is a perception that the ESR meter does not need very high accuracy, in practice, proven that EPS is a faulty capacitor in times more than in the running element.
The manufacturing process of the device starts with the fact that modeled the circuit in LTspice. The names of the main functional units you can see on the diagram.
The result of simulation is here is a chart that shows how far to deviate the arrow at the microammeter, including indicators of ESR.
Based on the results of the LTspice schematic is possible to construct the circuit in OrCAD. The device is powered using supply 9 V, and voltage regulation using IC LM7805. In addition, in order to make ESR meter with your hands, you will have to use transistors part no 2n3904 (NPN) and 2N3906 (PNP), however, the normal operation of the scheme will be provided by any common transistors. In the selection of the diodes will focus on the 1N5711. Current measuring head is 50 µa.
The value of the maximum voltage at terminals of the measured capacitor is not more than 100 mV, which gives the opportunity to use the device during in-circuit (without watering capacitor) testing.
Here you can see the appearance of the wiring Board, it is one side, and there are no jumpers. Try to use SMD elements, although some of the mounting holes will still need.
Printed circuit Board fabrication was carried out on CNC machine, milling was carried out tracks, however, it is possible to use LUT-om either the photoresist.om
The image shows a Board that has already soldered components:
Measurement values on the scale is performed by the method of practical use, using the connect precision resistors having different resistance in the range of 0.1 — 10 Ohms. Panache scales be made using CorelDraw and then scale prints using photo paper.
The Assembly process being completed. The image shows the inner side of the ESR meter.
And here’s the finished instrument:
Before the measurements it is necessary to produce a discharge of the capacitor. When the current supply 26 mA if powered from a battery “Crone”, the continuous operation can be performed during the day.
Well, that’s all! Now you can make ESR meter with your hands. Just need a little patience and a minimum of tools.