Among electronic components, there are products that have firmly occupied certain market niches for many decades. They succeeded due to a successful combination of cost, technical parameters, weight and size indicators. Such devices include a series of silicon diodes 1N4001-1N4007. They are unrivaled in their field.
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Description of 1N400X Series Diodes
The most popular series of single-ampere silicon rectifier diodes among developers, manufacturers and amateurs is 1N400X, where X = 1 ... 7 (indicates the number of the device in the series).
Diodes are produced in a DO-41 package, specially designed for two-terminal semiconductor devices designed for relatively high currents and voltages. It is a cylinder made of non-combustible polymer and two wire leads. The cathode is marked with a white (silver) annular band. Another package name is DO-204-AL. Also used marking SOD-66.The dimensions for this case are:
- plastic cylinder diameter - 2.04 ... 2.71 mm;
- cylinder length - 4.07 ... 5.2 mm;
- output diameter - 0.72 ... 0.86 mm;
- output length before molding - 25.4 mm.
You can bend the leads at a distance no closer than 1.27 mm from the body.
All devices of the series have the same dimensions, so you can distinguish them within the line only by the inscription on the case. Unfortunately, diodes from unknown manufacturers do not always have such markings. The 1N400X series devices are used very widely. The release of huge batches allows you to keep the wholesale price for diodes no more than a few cents apiece, and this also serves as the reason for the frenzied popularity of the product.
Main technical characteristics of diodes
Diodes of the 1N400X series, in addition to the maximum operating current of 1 A, combine the following parameters:
- the highest current in the pulse (duration 8.3 ms) - 30 A;
- the largest voltage drop in the open state is 1 V (usually 0.6 ... 0.8 V);
- operating temperature range – minus 55…+125 °С;
- the longest soldering time, / at a temperature, is 10 s / 260 ° С (although no one has yet been able to disable this diode during soldering - and even change its parameters);
- thermal resistance (typical value) - 50 ° C / W;
- the largest weight is 0.35 grams;
- the highest reverse current (at the highest reverse voltage) is 5 μA.
The remaining parameters differ for each last digit in the device designation:
| Diode type | 1N4001 | 1N4002 | 1N4003 | 1N4004 | 1N4005 | 1N4006 | 1N4007 |
|---|---|---|---|---|---|---|---|
| Maximum reverse voltage (constant), V | 50 | 100 | 200 | 400 | 600 | 800 | 1000 |
| Peak reverse voltage (pulse), V | 50 | 100 | 200 | 400 | 600 | 800 | 1000 |
| Permissible RMS reverse voltage, V | 35 | 70 | 140 | 280 | 420 | 560 | 700 |
Diodes of this series are designed for mounting in any position.
Compared to switching diodes, the 1N4001 - 1N4007 series devices have a fairly large capacitance - about 20 pF without applying voltage. This reduces the frequency range of the rectifier elements, but amateurs use them as varicaps.
These low frequency diodes are not designed to work as switching elements. The manufacturer does not regulate their on or off time.
Applications of 1N400X Series Rectifier Diodes
The scope of diodes is determined by their technical parameters. Lacking high frequency response, the 1N400X is mainly used in rectifier applications. But this scope is extremely wide, almost any mains-powered device has this node. The small size and low cost of diodes make it possible to connect them in parallel where there is not enough maximum operating current and in series where there is not enough voltage - in some cases this is more profitable than using diodes with improved characteristics.
Also, rectifier diodes are used to connect in parallel with inductances to "cut off" the negative pulse during switching. For example, if you manage electromagnetic relay using a transistor switch, then a surge of reverse voltage will occur during switching, and the transistor may fail. To avoid this, the relay winding is switched on in parallel semiconductor diode positive cathode. The diode does not affect normal operation, but "eats" the negative surge.
Also, devices of this series can be used to avoid connecting the power supply with the wrong polarity. It should be borne in mind that the voltage drop in the open state across the diode can reach 1 V.This can be critical at supply voltages of 5 V and below. In this case, it is necessary to use germanium devices.
Domestic and foreign analogues
There is no complete domestic analogue of diodes (case, series, line characteristics). Therefore, the replacement must be approached creatively based on the availability of space for installation.
The best option - KD258 in a glass case ("droplet"). The parameters are largely the same, and there will be no contradiction in terms of installation dimensions. It is necessary to pay attention to the most popular domestic diode for a current of 1 A - this is KD212 (with reverse voltage 200 V). Replacement is somewhat difficult due to the size mismatch. The dimensions in the plan allow you to put KD212 instead of 1N4001 - 1N4007, but the height of the Russian diode is 6 mm versus 2.7 for the foreign one, so you need to look at the presence of free vertical space. It also makes it difficult to directly replace the fact that the distance between the leads of the KD212 is only 5 mm, and the leads of the 1N400X can be bent at a distance of at least 8 mm (case length plus 2x1.27 mm). And it also makes direct replacement difficult.
If it is known for sure that the actual direct operating current is much less than 1 A, then you can try to replace the foreign device with KD105 or KD106. Their maximum forward current is 0.3 A (reverse voltage, respectively, 800 and 100 V). These diodes are similar in shape to the 1N400X, although they are larger. KD105 also has tape leads, which creates additional problems for installation in existing holes. But you can try to solder directly to the tracks on the back of the board.
If the operating current KD105 (106) is not enough, then there is an option to replace it with KD208. Here you will also have to solve the problem of an increased package size, as well as ribbon outputs. You can look for other analogues that are suitable in terms of parameters - there is nothing super-outstanding and unique in the characteristics of the 1N400X series.
Of foreign diodes, it is excellent for replacing HER101 ... HER108 - a one-ampere diode in the same package. It costs more, because its characteristics are higher - reverse voltage up to 1000 V. This device has a high speed. But with such a replacement, these parameters are not used.
You also need to pay attention to imported products:
- HERP0056RT;
- BYW27-1000;
- BY156;
- BYW43;
- 1N2070.
In many cases, these devices can replace the 1N400X, but in each case, you need to look at the parameters.
The need to find an analogue is a rare case. Diode 1N400X is sold in any electronics store, you can get it from any defective donor device. In this case, before installation, it is necessary to check the serviceability of the semiconductor device.
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