| ??? 04/24/06 07:50 Read: times Msg Score: -1 -1 Didn't Search First |
#114857 - Trying to drive 12v relay using tr557 |
Hello everybody.
I am trying to drive 12v(coil)relay through tr557 with base connected to p89c51rd2 (p2.0). vcc to mcu is 5v and vcc to transistor is 12v. As soon as I connect the Base to p2.0, the relay gets active, without any control of mcu. When same thing is tested with 5v(coil) relay in same circuit, everything is fine. Can somebody tell me, what changes to be made in transistor biasing. I am connecting a 4.7k resistor in series of transistor base and P2.0 in case of 12v relay. Collector to relay coil and emitter to +12v. |
| Topic | Author | Date |
| Trying to drive 12v relay using tr557 | 01/01/70 00:00 | |
| Search! | 01/01/70 00:00 | |
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| What is tr557? | 01/01/70 00:00 | |
| Deja vu | 01/01/70 00:00 | |
| Do not connect PNP with 12V to port pin | 01/01/70 00:00 | |
| 12V relay with BC547 drive Thanks to all | 01/01/70 00:00 | |
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