| ??? 02/07/06 17:22 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#109432 - Simple, cheap, small Responding to: ???'s previous message |
Hi Grant,
This is one way of doing it: 
This is a quick copy/paste of a circuit I designed recently. Here, T6 switches power to IC2 and that, basically, is that. Connect a port pin to the gate of the FET and you're ready to go. A '0' switches the load on, a '1' switches it off. For a 70mA load, you could use just about any FET that has an RDSon of say 2Ohms or less. What you really must observe in your choice of FET is the gate threshold voltage (VGS(th). This should be as low as possible, preferably around 1V. Check out Zetex, they have a good range of low voltage MOSFETs. The ZXM61P02, for example, is a 20V, 0.6Ohm device with a VGS(th) of 0.7V and costs only a few cents. Best regards, Rob |
| Topic | Author | Date |
| Powering a peripheral from a pin | 01/01/70 00:00 | |
| well, yes and no | 01/01/70 00:00 | |
| Simple, cheap, small | 01/01/70 00:00 | |
| Thanks Rob | 01/01/70 00:00 | |
| consider adding an RC circuit if ... | 01/01/70 00:00 | |
| Good point | 01/01/70 00:00 | |
| Indeed | 01/01/70 00:00 | |
| Nice solution! | 01/01/70 00:00 | |
| How about 4N35? | 01/01/70 00:00 | |
| Mmmh, I doubt it | 01/01/70 00:00 | |
| Bipolar Transistors | 01/01/70 00:00 | |
| Bipolar Transistors | 01/01/70 00:00 | |
MOSFET | 01/01/70 00:00 | |
| BC327 and 4mA base current | 01/01/70 00:00 |