To determine resistor resistance, it is the simpler and most reliable to measure it by an ohmmeter or a multimeter. However such way is not always available, since elementary lack of the necessary device, finishing with physical inaccessibility of a detail. Besides, before measurement of resistance of the resistor it it is necessary vypayat from the scheme, and it is not always possible. In this case determination of resistance of the resistor on its marking will help.
It is required to you
- resistor, ohmmeter, multimeter, magnifying glass.
Instruction
1. The easiest way to determine resistor resistance – to learn about it from the corresponding documentation. If the resistor is acquired as an independent detail, find accompanying documents (consignment note, the warranty card, etc.). Find in them resistor face value. Most likely, the size of resistance will be specified near the name of a detail, for example, resistor 4.7 K. In this case the number is meant by the resistor face value, and a letter (letters) – unit of measure. Options K, to, KOHM, kOhm, Côme, a lump correspond to kilohms. Similar designations with letter "M", instead of "to" - to megaohms. If the letter "m" is lower case (small), then theoretically it corresponds to millioma. However in practice such resistors usually are not on sale, and are manufactured independently of several rounds of a special wire. Therefore combinations with the letter "m" can be carried to megaohms (in non-standard cases better nevertheless to specify). The absence after number of unit of measure or existence of the word "Ohm" or "ohm" means, respectively, Ohms. (in practice can mean that the seller just did not specify unit of measure).
2. If the resistor is a part of the electric (electronic) device, take the electric circuit of this device. If there is no scheme, try to find it in the Internet. Find the corresponding resistor on the scheme. Resistors by small rectangles with the lines leaving the short parties are designated. In a rectangle, hyphens can be located (designate power). Near designation of the resistor letter R and some number designating serial number of the resistor in the scheme, for example, of R10 is (rectangle) usually. After designation of the resistor its face value is specified (is slightly more right or below). If resistance of the resistor is not specified, then look in the lower part of the scheme – sometimes the face values of resistors (grouped in values) are there.
3. If you have an ohmmeter or a multimeter, then just connect the device to conclusions of the resistor and write down indications. Previously switch a multimeter to the mode of measurement of resistance. If the ohmmeter "reads off scale" or on the contrary, shows very small value, adjust it on suitable range. If the resistor is a part of the scheme, then previously to its vypayayta, otherwise instrument readings for certain will be incorrect (smaller).
4. The face value of the resistor can also be determined on its marking. If designation of face value consists of two figures and one letter (it is typical for old "Soviet" details), then use the following rule: The letter is put to the place of a decimal comma and designates a multiple prefix: To – kilohm; M – megaohm; Е – units, i.e. in this case Ohms. If resistor face value – an integer, then the corresponding letter is put at the end of designation (69K = 69 kOhm). If resistance of the resistor is less than unit – the letter is put before number (M15 = 0.15 megohms = 150 kOhm). The letter is in fractional face values between figures (9E5 = 9.5 Ohms).
5. For the designations consisting of three figures remember the following simple rule: to the first two figures it is necessary to add so many zero how many it is designated by the third figure. For example, 162, 690, 166 it is deciphered as follows: 162 = 16’00 Ohms = 1.6 kOhm; 690 = 69’ Ohm = 69 Ohms; 166 = 16’000000 Ohms = 16 megohms.
6. If the face value of the resistor is designated by color strips, turn it (or turn) so that separate (remote from three) the strip was on the right. Then, having used the below-submitted table of correspondences of flowers, transfer colors of strips to figures: - black - 0; - brown - 1; - red - 2; - orange - 3; - yellow - 4; - green - 5; - blue - 6; - violet - 7; - gray - 8; - white - 9. Having received three-digit number, use the rule described in the previous point. So for example, if colors of three strips are located in following an order, that is from left to right (red - 2, orange - 3, yellow - 4), we receive number 234 which corresponds to the face value of 230000 Ohms = 230 kOhm. By the way, it is very easy to remember the above-stated table. The order of average flowers corresponds to a rainbow, and extreme colors by the end of the list become lighter.