Relay Driver Current

FvM said:

Makes only sense if you replace the relays by 9V type. Otherwise you need to drop down the voltage with series resistor, same overall power consumption as if supplying the relays by 5V linear regulator. Or use 9 to 5V switched mode regulator.

Click to expand...

The 9v supply powers the Reference voltage IC, and the dedicated 5v regulator for Arduino.
Operating the coils from 9v Battery should be fine, power consumption was not the consideration.

Relays JQC-3FF-05:
https://www.futurlec.com/Datasheet/Relays/JQC-3FF.pdf#page=1&zoom=auto,-32,842

Specifications: 5V 1/2/4/6/8 Channel Relay Board Module Optocoupler LED for Arduino PiC ARM AVR

I purchased the above Optocoupled Relay Boards from Ebay: **broken link removed**

On arrival I Googled the components on PCB.
LM2596
3-A Step-Down Voltage Regulator

PHOTOTRANSISTOR/PHOTOCOUPLER
DPC-817C
Collector-Emiter Voltage = 35v.

8ch Darlington Sink Driver
ULN2803APG

202 = 1k resistor.

Relays JQC-3FF-05-1Z SPDT
https://www.futurlec.com/Datasheet/Relays/JQC-3FF.pdf#page=1&zoom=auto,-32,842



If you purchased 5V 1/2/4/6/8 Channel Relay Board Module Optocoupler LED for Arduino PiC ARM AVR from Ebay
A good description can be found here: **broken link removed**

Relay Module board – 16 channel with optoisolators and LM2596 PSU
Product Description

Controlling larger systems is easy with this sixteen relay module. The relays are opto-isolated from the control circuit, and the board contains it's own power supply circuit based around the LM2596. The inputs are 3.3V tolerant however the control circuit requires 5V - so it can be controlled from your Arduino, Arduino Due, Raspberry Pi, or other 5V or 3.3V development board along with TTL outputs and so on. Please note that control lines are active LOW (so a HIGH signal turns a relay off, a LOW turns it on)

Specifications

Relays - 250V AC 10A or DC 30V 10A
Size: 18cm x 9cm x 1.8cm

Instructions:

Review the end of the relay board as shown below:



1/ Connect between 9 and 12V DC with at least 500mA to the blue terminal block - this is the power supply feed for the relay coils, and is electrically isolated from the control circuit.
2/ Connect 5V from your microcontroller board (e.g. Arduino 5V pin) to either one of the 5V pins at the left-hand side of the input pins
3/ You don't need to run a GND wire from the microcontroller board - do not connect this to the terminal block's GND side
4/ Connect a line from each digital output on your microcontroller board or other circuit to pins 1~16 of the input pins respectively. Each of these will trigger a relay. The inputs are active low - so a high signal (3.3~5V) turns a relay OFF, 0V turns it ON.