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I'm trying to make a bipolar H-Bridge motor driver. But instead of the mentioned diode(1N4001), I've got a 1N4007 diode. Can I use that instead?

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Be aware that they are virtually identical, except the 4007 is more expensive and may have a slightly higher capacitance (which shouldn't matter anyway, because 1N400x's are not designed to be operated in high speed circuits.) – Thomas O Nov 28 '10 at 13:43
Some prof once told me that 1N400x's are all made the same, just graded differently based on how they turn out. Not sure how much I believe that, but if you look at some datasheets all specified parameters are the same except Vr and only two different capacitances (maybe they just make 1N4004 and 7's?) – Nick T Nov 28 '10 at 16:11
"maybe they just make 1N4004 and 7's?" Probably the manufacturing process has improved so much that it is not worthwhile to make the others. – starblue Nov 28 '10 at 20:06

1 Answer

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Yes. The 1N4007 can withstand a higher reverse voltage(\$V_r\$), 1000V vs. 50V. The 1N4007 may even be a better choice, esp. if your motor is powered by a voltage near 35V. (The 1N4001 is rated for a \$V_{r(RMS)}\$ of 35V.)

While diodes like 1N400x may be well suited as freewheeling diodes in terms of voltage and current (rated at 1A), they're not exactly fast. To protect your transistors Schottky diodes would be a better choice, but they usually have limited \$V_r\$.

Here's the \$V_r\$ for the 1N400x series:

1N4001: 50V
1N4002: 100V
1N4003: 200V
1N4004: 400V
1N4005: 600V
1N4006: 800V
1N4007: 1000V

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"not exactly fast" could be an issue with higher frequency PWM. There are a lot of PWM projects that run at 300 or 400Hz, for which 1N400x would be ok, but then there are designs with 8, 10, even 20kHz PWM where the 1N400x just won't cut it. – JustJeff Nov 28 '10 at 14:45
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There are fast recovery diodes that are not Schottky, if you need a higher reverse voltage. Search your favorite distributor for "fast recovery." These are not as fast as a real Schottky, but much faster than 1N400x. – markrages♦ Nov 28 '10 at 19:54

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