Hello all.
I dont know to answer but because i have a question about relays and relays modules
i choosed to post here to be easier for someone in future to solve his issues.
First of all ,,,i am very beginner in arduino and microchip programming
and ....i have almost no idea about electronics !!!
Lets try my 1st and main question.
1.Ok...i ve managed to finish my 1st arduino project that is
A load scale (10 kg) sending sms 1 per day ....from gms in some phone number.
And i bought a relay MODULE that already has transistor,resitors and diode...(and 2 leds)
You can see on attached image

Now the problem is that i DONT want to use the hole MODULE
because
a)i need to shrink the things
b)I dont want the led of the module
c)i want to learn
As so,,,The question is.
-Can i use a SINGLE relay (not module) with
ONLY one DIODE (just before the wire coming from the pin that i am controlling
with digitalWrite(Pin, LOW or HIGH) the relay ?
...avoiding the TRANSISTOR and RESISTORs ??????
If yes,,,,is there (on the market) RELAYS (not modules) that can be triggered with
the few amperes 20mA of arduino?
2nd question ....maybe stupid but forgive me.
In the above module...that i installed fine and working fine
-WHY i must use 3 (Vcc,Grnd, Controlling Pin)
and not 2 ( Grnd ,Controlling Pin) [avoiding Vcc]
wirings from arduino ?
I just want to give HIGH (if digital) or 255 (if analogue) to the controlling PIn
so that when has voltage will give it to the RELAY
in order for the COIL to function and have the results on the OTHER side
( on the other non relative CIRCUIT... Normally open or normally close depends etc)
PS...I ve tried also with analogueWrite (2 wires)but not succesfully)
...I dont know...if this question is understandable...
Also the strange thing is that i must give LOW to trigger the coil ..
but i was expecting ....that i am suppose to give High to trigger and low to rest
...in order ..also ..to avoid baterry-energy consumption...
Thank you in advance anyway ..
