Timeline for Tip120 simulation shows explosion
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 15, 2018 at 6:50 | vote | accept | user482963 | ||
| Nov 15, 2018 at 6:50 | vote | accept | user482963 | ||
| Nov 15, 2018 at 6:50 | |||||
| May 14, 2018 at 7:56 | vote | accept | user482963 | ||
| Nov 15, 2018 at 6:50 | |||||
| May 13, 2018 at 22:30 | answer | added | Spehro 'speff' Pefhany | timeline score: 2 | |
| May 13, 2018 at 18:00 | answer | added | user482963 | timeline score: -1 | |
| May 13, 2018 at 17:36 | comment | added | user482963 | @SpehroPefhany I did provide the motor ratings.. 5V, 3W, 600mA. I am applying 0.6 mA base current and base resistor is at 4.1k to drop volts down to 2.5V as VBE is 2.5 according to datasheet. What else am I missing? I will apply the flyback diode and post back..thanks | |
| May 13, 2018 at 17:28 | comment | added | Spehro 'speff' Pefhany | Did you try the flyback diode? When the transistor turns off (not on) the voltage will likely spike up to cause the transistor to break down, at least in your simulation. Depends on how far from reality your motor model is. If it's just a resistor that won't happen in simulation. If it's a pure inductor + series resistor it will happen. Neither represents a motor load very well. A stalled motor will draw considerably in excess of its running current. I hope you recognize that you have provided woefully inadequate information. | |
| May 13, 2018 at 17:09 | comment | added | user482963 | @SpehroPefhany well that seems right because VCE is 2V..so that leaves 3V but still does not explain the explosion | |
| May 13, 2018 at 17:07 | comment | added | user482963 | @SolarMike which part of rating that might be? The motor here is rated at 4.5V only. Well I tried 2N2222A and 2N3904 but had similar result | |
| May 13, 2018 at 15:52 | comment | added | Spehro 'speff' Pefhany | You need a flyback diode across the inductive load. I don't know if your simulation is picking that up- you should provide simulated base current and collector current values or we are just guessing. A Darlington is really not a great way to switch 5V since it will leave you with only about 3V for the motor. A logic-level MOSFET is preferably. | |
| May 13, 2018 at 15:37 | comment | added | Solar Mike | Does the motor current exceed the transistor rating? | |
| May 13, 2018 at 15:34 | history | asked | user482963 | CC BY-SA 4.0 |