Timeline for Circuit to drive a Solid State Relay
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Apr 4, 2013 at 6:22 | comment | added | jippie | @Brad there is also a absolute maximum rating per package: DC Current VCC and GND Pins 200mA. They're pretty easy to meet driving couple LED's at 20mA. | |
| Apr 3, 2013 at 21:55 | vote | accept | Brad | ||
| Apr 3, 2013 at 20:54 | comment | added | angelatlarge | @jippie: Maybe I did invent this after all: I thought I saw it in ATmega datasheets, but now I can't find it. Thank you. | |
| Apr 3, 2013 at 20:52 | comment | added | Brad | The 40mA number is an "Absolute Maximum" on the ATmega328. There are all sorts of maximums you can not exceed across MULTIPLE ports and/or pins. 20mA is the "test condition" written in the datasheet. Thus, it seems I can go as high as 40 (in a pinch) if I'm not driving much on other pins (which I am not). But 20 as calculated target should be fine in this condition. | |
| Apr 3, 2013 at 20:43 | comment | added | jippie | @angelatlarge do you have a reference to "most (all?) chips that Arduino is built on do provide over-current protection"? | |
| Apr 3, 2013 at 20:43 | comment | added | Brad | I think the "Isolation" of the SSR is with respect to the AC vs. DC sides (or load vs. input sides) - whereas the isolation being discussed is isolating the Arduino from the input side. | |
| Apr 3, 2013 at 20:33 | comment | added | angelatlarge | On point 1, most (all?) chips that Arduino is built on do provide over-current protection, so I don't think it is true that you will "burn out your chip". Secondly, isn't "isolation" exactly what SSRs are built for? Sure two layers is more safe, and three is even safer, so where do you stop? | |
| Apr 3, 2013 at 20:32 | comment | added | jippie | 40mA for the ATmega's I am aware of, hence the importance of the datasheet. | |
| Apr 3, 2013 at 20:25 | history | answered | xyzio | CC BY-SA 3.0 |