Timeline for Why did my transistor break?
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 12, 2020 at 10:23 | comment | added | Kinka-Byo | Perfect, thank you very much! | |
| Sep 12, 2020 at 8:39 | comment | added | Andy aka | @Kinka-Byo I'd probably put 100 nF across the motor to catch any glitches. I'm not sure about the zener only being rated at 5 watts and 24 volts. You power supply could be 27 volts and, on full motor drive the zener may burn out. | |
| Sep 12, 2020 at 7:48 | comment | added | Kinka-Byo | @Andy aka Thank you again. I have put my modifications in the question, with my final schematic. What do you think of all these protection systems? | |
| Sep 11, 2020 at 16:35 | comment | added | Andy aka | To protect an NPN transistors base emitter from excessive reverse bias, the anode connects to the emitter. Remember that you may need to do other protections too and I did advise you to draw a circuit and let me see it. | |
| Sep 11, 2020 at 16:00 | comment | added | Kinka-Byo | @Andy aka Sorry for asking this clarification, but how should I connect the reverse diode? Anode to Base and Cathode to Emitter? | |
| Sep 5, 2020 at 12:47 | comment | added | Andy aka | @Kinka-Byo there are several ways to do this and my recommendation across base and emitter directly address why I think the transistor broke. You may find that you do need both methods. Again, if you come up with a scheme, post it and I'll take a look. | |
| Sep 5, 2020 at 12:40 | comment | added | Kinka-Byo | Perfect, a last question: why should I put the diode between base and emitter instead of in parallel with the motor (which I am seeing on the web it is a common configuration). What if I put a diode between base and emitter and another diode in parallel to the motor? Will it be safer? | |
| Sep 5, 2020 at 0:38 | vote | accept | Kinka-Byo | ||
| Sep 4, 2020 at 19:48 | comment | added | user2121 | @Kinka-Byo If you found this answer solved your problem then you should accept it as the correct answer.. | |
| Sep 4, 2020 at 18:27 | comment | added | Andy aka | It shouldn't need one - it would go across base and emitter and doesn't need a resistor. Maybe if you have a cunning idea you should draw a circuit and let me look? | |
| Sep 4, 2020 at 17:25 | comment | added | Kinka-Byo | A series resistor for the reverse diode. | |
| Sep 4, 2020 at 16:57 | comment | added | Andy aka | What series resistor? | |
| Sep 4, 2020 at 16:38 | comment | added | Kinka-Byo | Perfect, thank you. Why do not I need a series resistance? | |
| Sep 4, 2020 at 12:15 | comment | added | Andy aka | You should be able to get away with a 1N400x diode across base and emitter. | |
| Sep 4, 2020 at 9:02 | comment | added | Kinka-Byo | Thank you for your advises. I'd say that the problem is not the heat, since the transistor was not so hot after the accident. So, I'll change it with another BUV20 and I'll put the capacitor and the reverse diode. Then, I'll test the device again. About the reverse diode, how can I choose it and its series resistance if I do not now the possible values of back emf? | |
| Sep 4, 2020 at 8:23 | history | edited | Andy aka | CC BY-SA 4.0 |
added 222 characters in body
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| Sep 4, 2020 at 8:15 | history | answered | Andy aka | CC BY-SA 4.0 |