Household multimeter, which I have not found on the market
Having thrown out another dead DT-838, I thought hard. The market is full of multimeters at any price and measurement accuracy. But when you need a simple household multimeter that is needed on the farm: for simple repair of household appliances, cars, electrical work, there is essentially nothing on the market other than DT-838. But everything cannot be so sad, I argued, for sure there must be some other devices in the purgatory between the indicator screwdriver, the probe-bulb and the DT-838. Who would look harmoniously in the tool box, extracted from there every six months for rare works, or would live in a car all year round. There were no such, and therefore all that will be written below is an attempt to describe the desired multimeter, starting from the demands made by the everyday life of an ordinary person, far from electronics, but with straight arms.
Looking ahead, I will say that I found something similar to the ideal in the YX-1000A, YX-2000A, YX360TRN devices, but unfortunately the weather on Mars, so accurately shown by these devices, still interests me less than the car battery voltage measured at the moment . Otherwise, he could be forgiven for even the absence of a sound dial. It seems that the Chinese did not even try, because I cannot explain the error to 30% otherwise.
But it was this device that prompted me to the idea that a household multimeter should be an arrow. Firstly, for domestic use, the accuracy of a cheap switchman is quite acceptable. Secondly, this will make it possible to make at least some of the functions available without a battery, such as voltage measurement. Batteries like to waste away in disregard, especially in devices of people living in a self-service barn, when the temperature can walk from +50 to minus some there. It is best to deal with a sudden forced autodiagnostics with a working measuring device. Similarly, at home - the device can lie without use for a couple of years, if your life is well-established. At the end of the theme of arrows, I can add that it is useful to see transients, just to see where the circuit is open and where contact is bad.
The accuracy of dial gauges is usually inferior to digital ones. Especially the accuracy of cheap analog multimeters of cheap analog multimeters. This happens not only because of the special design of the switch gear, but also because of the inevitable process of price reduction to which each circuit is subjected. So, sooner or later, from the device modifications, the first trimming resistor will disappear, and then the usual resistors will change the tolerance class to the point that it will be impossible to use the device. To combat this, I only see it possible to throw out as many measurement ranges as possible in order to reduce the elemental base, and compress the ranges themselves so that, on the one hand, they are more suitable for domestic needs, and on the other, make the arrow walk with a small error, that even Chinese aunts on the assembly line saw that it's not a scale. Well, it will be possible for ourselves not to squint our eyes to the state of the Chinese apostles, in order to make out the number under the arrow.
There are slightly more expensive dial instruments like the YX-2000A and YX360TRN, but they have about the same problem in household use - a bunch of universal ranges, for measurements in which they usually buy a normal device. Moreover, these switches will cost more expensive all the same DT-838 with the worst indicators of accuracy.
Without a battery, we can measure the DC and AC voltage, its strength. Let's start with DC. Remembering that we are dealing with a switchman, for greater accuracy within the range and readability of the result, I would single out 2 scales:
- 0 - 6 volts. To check the batteries, except for the crown, lithium-ion batteries, power supply cell phones. A small range, but here a deviation of half a volt can be decisive.
- 0 - 30 volts. To check the lines of computer power supplies, laptop power supply, car battery.
As for the alternating current, one scale up to 400 volts is enough in principle. Provided that the error is not more than 5%. This accuracy will be enough to understand whether you have correctly connected the phases to the electric cooker, and also whether the mains voltage has subsided to the extent that the observed malfunctions of the electrical appliances can be caused by its drop.
Measuring DC power is more difficult. The ranges used on modern cheap multimeters seem to me of little use for everyday life. This is usually conditional 2 modes - from 0 to 500 mA, and up to 10 A. The modes can be more, but usually they sit on two fuses - 0.5 and 10A. The problem is that phones, tablets and everything that is powered by USB today eats from 500 mA and higher. Is that the leakage current of the onboard vehicle network can be checked in this mode. But if you measure the lower range of 0-10 A, then the accuracy will be useless and look at the switchman will be hard. I think that ranges are better to do this:
- 0 to 200 mA. The leakage current in the car, the current consumption of LEDs.
- 0 - 4 A. USB charging, power supplies for small household appliances. Some consumers of the onboard network of the car, get into this range. Malfunctions in those that consume more, you will most likely find out by the blown fuses.
I do not know how possible the measurement of AC power on the switch instrument without significant complication and cost of the circuit. And as far as is justified, since I can not remember the situation when I would have to measure the current consumption of household appliances. In the sense, it is usually written on it either, or is it something TEN-ovoy, which eats more than 10 A, or the technology has already died, thereby signaling that it is not all right with current consumption.
Now features that require a battery. Sound dialing, everything is clear, but at least LED, but at least some. Here you can also push and dial the diodes / LEDs. Ideal so that the diode caught fire. For this you can even stand the power of two AA batteries. The krone is a convenient battery just to lick it off. In other cases, AA, in extreme cases, AAA batteries are much more common. Especially the target audience of an imaginary multimeter.
Measurement of resistance can also be limited to a pair of ranges.
- 0 to 200 ohms. Allows you to check the windings of transformers, the serviceability of power cables, as well as some short-circuits that are not pierced by a continuation dial.
- 0 - 2 MΩ Allow you to search for wiring with partially broken insulation and measure the resistance of your body.
Of course, you can also add a frequency meter and a 50 Hz pulse generator, so that you can check the speakers, headphones and their wires, but this is from the evil one.
But in general, that's all. It seems to me that the imaginary device described above, made in a copus, for example, the same YX-1000A or YX360TRN, and with a guaranteed error of no more than 5%, would be very popular. But who will make it?
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