| ??? 01/27/06 07:20 Read: times |
#108472 - ULN2803,ULN2003 Responding to: ???'s previous message |
Hi Abdul,
You already given a lot of useful info by other members. Since ULN2003's are pretty broadly available i suggest you to use them. In this example you stated that you're into the need of driving 8 relays . ULN2803 could drive 8 relays while ULN2003 could drive 7 . ULN2803's are a little hard to find. Coils produce back EMF when they turn off. this back EMF could be damped by the ULN driver IC without any external Diode (You will need to connect the anode of internal diodes to the relays supply). As for the relays when you buy one there are some informations printed on the relay : - Coil drive voltage (DC/AC , 5,12,120,240,... Volt) This is the voltage you have to supply for the relay to be turned on. I suggest you to go for 5V or 12V DC ones. - Contacts (NO,NC,C Amperage , Voltage ) Here the number of the contacts can be seen. You can switch every load by the contacts as far as you don't violate the contacts rating.So if you want to switch a mains light rated at 4 Amp I suggest you to go for a relay with 240V and 10 Amp rating. Farshid |
| Topic | Author | Date |
| Relay board diagram | 01/01/70 00:00 | |
| Just search for, "Relay" !! | 01/01/70 00:00 | |
| andy Neil | 01/01/70 00:00 | |
| Relay ratings | 01/01/70 00:00 | |
| ULN2803,ULN2003 | 01/01/70 00:00 | |
| more on relay ratings | 01/01/70 00:00 | |
| Yes of course | 01/01/70 00:00 | |
| internal diodes | 01/01/70 00:00 | |
| ULN2003's doesn't easily burn | 01/01/70 00:00 | |
| Uce saturation voltage is rather high | 01/01/70 00:00 | |
| there is an alternative, search for it | 01/01/70 00:00 | |
| I agree | 01/01/70 00:00 | |
| That is bad design | 01/01/70 00:00 | |
| ULNs resist more... | 01/01/70 00:00 | |
| I would never suggest 74HC buffers for d | 01/01/70 00:00 | |
| Yes , you didn't | 01/01/70 00:00 | |
| I would like to see where that is, pleas | 01/01/70 00:00 | |
correct link | 01/01/70 00:00 | |
| Bad Design? | 01/01/70 00:00 | |
| naah | 01/01/70 00:00 | |
| Also depends on transistor speed | 01/01/70 00:00 | |
| valid issue, but not that, now another | 01/01/70 00:00 | |
| Indeed | 01/01/70 00:00 | |
| Serial | 01/01/70 00:00 | |
| How much current? | 01/01/70 00:00 | |
| allegro | 01/01/70 00:00 | |
| and infineon | 01/01/70 00:00 |