Studying the technical specifications of 1N4001, you can see that we have one of the weakest rectifier diodes from the 1n400x series. If we compare such devices according to the parameters taken from a separate datasheet, then the disadvantages will be obvious. So, in terms of the maximum values of supported voltages, the IN4001 is significantly inferior to its “brothers”, but otherwise it practically does not differ from them.
1N4001 Pinout
The 1N4001 is produced predominantly in DO-41 (DO-204AL) plastic cases. There are also devices in plastic packaging A-405, CASE59−10. All versions have two axial wire leads, which, in addition to the main purpose, are used as a heat sink (provided that they are correctly mounted on the board). The cathode side is marked with a light strip by the manufacturer.
There are also SMD versions of 1N4001(DO-214AC) for board surface mounting. In terms of their parameters, they practically do not differ from those discussed above, with the exception of the design of the plastic package. At the same time, almost all modern packaging versions comply with the European environmental standard EC 2002/95/EC (RoHS) and UL94-V0 fire resistance requirements.
1N4001 Specifications
- Peak Repetitive Reverse Voltage (VRRM) – 50 V;
- Working Peak Reverse Voltage (VRWM) – 50 V;
- DC Blocking Voltage (VR) – 50 V;
- Non−Repetitive Peak Reverse Voltage (VRSM) – 60 V;
- RMS Reverse Voltage VR(RMS) – 35 V;
- Average Rectified Forward Current (IO) – 1.0 A;
- Non−Repetitive Peak Surge Current (IFSM) – 30 A (for 1 cycle);
- Operating and Storage Junction (TJ) −65 to +175 °C;
- Temperature Range (Tstg) −65 to +175 °C.
Some datasheets point to the possibility of using the diode in various low power general purpose applications, power supply rectifiers, inverters, converters, and others. It is believed that the device has been specially adapted for operation in electrical circuits (up to 50 V) with an operating frequency of up to 60 Hz.
Consider the typical electrical parameters of the 1N4001 in the table below. The junction capacitance (CJ) is measured with a reverse voltage (VR) of 4.0 V, at a frequency of 1.0 MHz. All given values are valid only at an ambient temperature (TA) not more than +25 °C, taking into account the requirements for placing the device case from the circuit board at a distance of up to 9.5 mm.

It should be noted that earlier versions of the rectifier diode in question had better recovery times and higher junction capacitance (CJ) at all reverse bias voltages (e.g. 8pF vs. 15pF at VR=10V) when compared to 1N4005-1N4007. Currently, manufacturers indicate the same CJ value for the entire series.
Equivalents
Choosing an equivalent for 1N4001 is not a trivial task. The fact is that this device is quite widespread and available for purchase in almost any store. Low cost and good popularity contributes to its wide distribution and widespread use.
Despite all the advantages, sometimes situations arise when it is necessary to replace the 1N4001 with a more modern one. In such cases, foreign ones are well suited: EM513, EM516, EM518, but they will cost an order of magnitude more expensive. Therefore, most often, as part of the repair, they are changed to any rectifier diode from the 1N400x series.
Manufacturers
The most famous, at present, manufacturers of the considered diode are: Vishay Siliconix, Diotec, Onsemi (ON Semiconductor, Fairchild). Also on the market are devices from Chinese manufacturers Yangzhou Yangjie Electronic Technology, TAIWAN Semiconductor. You can download all the datasheet for the 1N4001 diode in a special section at this link.