Markings of Soviet resistors: designation features, power and resistance marking

Despite the fact that the times of the USSR have long since sunk into oblivion, there are still plenty of radio electronic equipment and radio components of that time. This suggests that people involved in electronics and other complex electrical engineering just need to know the designations of radio components, adopted at that time. So, the marking of Soviet resistors differs from modern counterparts, but it is just as clear and simple.

Soviet-made resistors

Unlike modern resistors, which have markings accepted throughout the world, Soviet radio components had their own standards and designations. For example, to understand what modern detail is before your eyes, you will have to turn to tables or online calculators.

For the Soviet counterparts, such difficulties were useless. They were designated simply and understandably to everyone, even a novice radio amateur.

A resistor is a semiconductor that has a certain specified resistance and is used to limit the currents in a circuit.

The main characteristics of resistors are:

1. Nominal resistance - indicated in ohms, kilo-ohms and mega-ohms. This value is always present in the diagrams.
2. Power dissipation - indicated in watts. As you know, passing through a semiconductor, the current heats it up. If a certain preset value is exceeded, it will begin to collapse. This is the power dissipation, that is, the value at which the semiconductor will work without damage to itself. The diagrams also indicate this value.
3. Nominal resistance tolerance - indicated as a percentage. Since it is impossible to create a resistor without deviations from the optimal values, you have to take into account a certain percentage of error. The nominal resistance tolerance indicates the percentage deviation from the specified resistance value.

Power marking

On both modern and Soviet parts, the designation of power was extremely important, since it is one of the main characteristics of a semiconductor. But this parameter can be determined without marking, especially if the master is experienced. It often happens that the markings are erased, chipped, or just poorly visible. However, this is not an obstacle to determine the power and resistance.

This can be done by the size of the resistor - the larger the case, the better it dissipates heat and, therefore, has more power. And the foundations of physics, in particular, the Joule-Lenz law, confirm this. Thus, the smaller the resistor, the less its power.

The power of Soviet MLT resistors, that is, a metal-film, varnished, heat-resistant element, began to be denoted from 1 W - MLT-1. Accordingly, 2 W - MLT-2, 3 W - MLT -3 and so on. For less powerful resistors, there was no power marking of resistors, and it could only be determined by the size of the case.

Resistance value

As for the letter marking of resistors in terms of resistance values, then everything is quite simple here. Both MLT resistors and other Soviet devices of this group resistance designation is expressed in alphanumeric sequence. Directly the value was displayed by a number, which is completely logical, but the ohms, mega-ohms and kilo-ohms had letter marking. If the letter R or E is applied, then the resistance value is counted in ohms. The letter K indicates that kilo-ohms are considered, and the letter M indicates the values ​​in mega-ohms.

For example, the given resistance will be 2 kilo-ohms, which means that the designation has the form 2K0. Another example: 33 MΩ resistance will be designated as M33. And the third example: the designation of the type 1K2 indicates that this is a one kilo-ohm and 200 ohm resistor.

Modern details

If we talk about the modern designation of resistors, then for some it causes certain difficulties, especially for people accustomed to Soviet counterparts. And the point here is not the complexity, but the laboriousness of the process. After all, you need to take a table, correctly determine the location of the colored stripes and after that still carry out, if not complicated, but still calculations. Although online calculators help with this, which save you from a lot of unwanted actions.

To decipher the colored stripes on the resistor, you must first hold it correctly. For this the golden or silver stripe should be on the right. Although if there are two such stripes or not at all, then to the left hand the stripes are located in such a way that they turn out to be shifted to the left.

There can be from three to six stripes. Each of them carries predetermined information, which can be read only by resorting to a table or an online calculator.

There are also SMD resistors. Their main feature is their very small size, which makes it difficult to read information from the surface. And to understand that it is a transistor, resistor or something else is not always easy for an inexperienced user.

As you can see, it is impossible to apply full marking even with colored stripes on such small objects. But you still need to do it. Therefore, as a rule, nothing is applied to very miniature ones, and it is customary to apply three numbers on parts that are slightly larger and have a tolerance of 10%. Of these, the first two indicate the denomination, and the third, to the power of ten.

As an example, we can take the designation 332. The first two digits are the denomination, and the third is the power of ten. So 33 times 10 squared, which is 3300. This number indicates that a 3300 Ohm part was taken or, if we bring it to normal, 3.3 kOhm.

Resistances with a tolerance of one percent or more are indicated by four numbers. Although this does not affect anything, since it is deciphered according to the same scheme: the last digit is the degree, the first three are the denomination.

In some cases, SMD parts can be marked with two numbers with a letter. And such a marking really causes a number of difficulties, since it obliges you to have a table by which you can calculate the nominal value of such a semiconductor. So, as an example, you can give the designation in the following form: 01C, where (according to the table) 01 is 100 Ohm, and the letter C says that the factor is 102.

So 100 ohms multiplied by a factor of 100 gives 10,000 ohms, which in turn equals 10 k ohms.

Designation on the diagrams

It is clear that the resistors themselves can be marked as you like, according to GOSTs or other standards. But on the diagrams, they are always indicated the same way, regardless of whether they are Soviet or modern copies. So, the schematic designation of such parts looks like an empty rectangle, inside which:

• Three vertical lines indicate that a 3W resistor is installed.
• Two of the same lines will say that a 2 W element is located here.
• One line speaks of a power of 1 W.
• If the line is one and located horizontally, then the power of such a resistor will be 0.5 W.
• One diagonal line from left to right indicates 0.25 watts.
• Two such oblique lines indicate parts with a power of 0.125 watts.

Other data can be located in digital and letter form anywhere, but it is always understandable for the reader of the diagram.

In any case, this is a Soviet resistor, modern, domestic or foreign, you can always read its designations and find out the data of interest. Thus, we can conclude that no matter how such a detail is designated, the master will always understand what it is and how it can be replaced.