1N40XX series diodes1N40 series diodes are one of the oldest and most popular rectifier diodes. This can be explained by availability, low price and acceptable parameters for most cases (average direct current of 1A, pulse current up to 30A, direct voltage drop of 1.1V).Within the series the diodes differ from each other only by the reverse voltage: from 50V for 1N4001 to 1000V for 1N4007.Thus any diode of this series can be replaced by a more high-voltage diode if needed.The diodes are released in a DO-41 case; a bright ring is applied at the side of the cathode. The diodes of this series are labeled according to the American system JEDEC, for example -- 1N4001 means a diode with a serial number 4001.The manufacturing technique of these diodes is quite developed therefore the diodes are produces by dozens of companies.KD243 series diodes from KD243A (reverse voltage of 50V) to KD243Zh (1000V) respectively are the domestic prototype of 1N40diodes.A color code is accepted for these diodes: for instance, this diode with a green ring is KD243G, and this diode with a white ring is KD243E. The rings are also applied at the side of the cathode. 1N40 series diodes also have a leadless package for surface mounting. The labels of such diodes start with a letter combination SM, SMA, LL, etc. For example, this is an SM4007 diode in a DO-213AB package (MELF -- in other words), and this is an SMA4007 in a DO-214AC package.
