| ??? 05/01/09 07:55 Read: times |
#164980 - Base current and transistor beta Responding to: ???'s previous message |
The problem, as the other replies indicate, is due to the fact that the 8052 port pin cannot source a lot of current. You don't say how much current the solenoid draws, so I don't know how much base current you need. Michael Karas's circuit will work, but a really simple solution is to use a logic level MOSFET instead of the TIP120 |
| Topic | Author | Date |
| Driving TIP120 from 8052 | 01/01/70 00:00 | |
| It is the Current | 01/01/70 00:00 | |
| Use this type circuit | 01/01/70 00:00 | |
| Thanks, I'll give it a try | 01/01/70 00:00 | |
| 0.1A | 01/01/70 00:00 | |
| Michael circuit is fine with some diff values. | 01/01/70 00:00 | |
| Success! | 01/01/70 00:00 | |
You use a Darlington, ... | 01/01/70 00:00 | |
| Check values | 01/01/70 00:00 | |
| is Q2 not a bit overkill? | 01/01/70 00:00 | |
| Base current and transistor beta | 01/01/70 00:00 | |
| logic level MOSFET | 01/01/70 00:00 | |
| they do make p-channel logic mosfets | 01/01/70 00:00 |