ESP8266 Community Forum

- Thu Jun 09, 2016 9:17 am #48859 I'm not good at electronics calculation. Try to control two relay. Is this schematic right about the device positioning and calculations and what are the easy calculation formuls

- Fri Jun 10, 2016 1:17 pm #48946 You don't show pull up resistors on D0 and D2, and no pull down on D15. I typically use 10K on those.

The resistors you picked for the transistors driving the relays would be adequate for a relay current of up to 5o mA. (considering a worst case current gain) If you need more than 50 mA then scale R3 and R6 down proportionally.

I also like to use a 0.1 uF capacitor at both the input and output of the regulator. In parallel with the 100 uF you show. At higher frequencies the larger value capacitors are less effective.

- Fri Jun 10, 2016 2:06 pm #48947 In addition to what rudy said, if you didn't purchased yet your BC847 transistors, it is better to use MOSFET, they are saturing more easily. You can use some 2N7002, or even better AO3402.
BTW, there is small typo on R4, with 10K value, your LED won't light up ...

- Sat Jun 11, 2016 12:07 pm #49005 @rudy Thx for your suggestions i changed the diagram, is this ready?

@martinayotte Thx for typo actually i dont understand how it is happen i copy the group
Is dual relay driver is better choice for less foot print.