Prime members enjoy FREE Delivery and exclusive access to music, movies, TV shows, original audio series, and Kindle books. What would the concequence be if you connect two seperate arbitrary grounds? We use the transistor as a switch to switch the 12V supply to the relay coil with as much current as needed (limited by the relay coil resistance). 4 years ago on Can some1 post diagram on how to use the relay with arduino with 12V 1A power supply to Arduino and no different power source for the relay. More Buying Choices $10.36 (2 used & new offers) 1 year ago You should use 1N4148 diode instead of 1N4007 as 4148 is a fast switching diode with maximum forward current of 300ma. The relay requires 30mA to pull-in. After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in.After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. 3 years ago 3 years ago 9-Volt battery) and the Arduino (USB cable) OR the Arduino board itself supplies the power but the relay is a 5-Volt one.If I may ask, would it be possible to use only 1 power supply (e.g. 3 years ago To connect a 12V relay to the Arduino you need the following things: – 1 Arduino – 1 diode for example 1N4007 – 1 NPN transistor for example 2N2222 (in the US) or BC548 (in Europe) – 1 relay for example one with coil voltage 12V and switching voltage 125VAC/10 A – 1 multimeter The detail instruction, code, wiring diagram, video tutorial, line-by-line code explanation are provided to help you quickly get started with Arduino. For example search for "2N2222 datasheet".The diode is needed cause the voltage will rise high if you suddenly change the voltage at the inductor. Note that including the 0.7V actually brings down R1 closer to the value homunkoloss chose (10k). Your recently viewed items and featured recommendations PLease help it really bugs me!! So it will pickup stray emf around you. Connect a resistor (any value from 10k to 1M) from analog pin to ground to fix that. 99

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Hi. 2 years ago

Think about the voltages that you are using as potential differences i.e the arduino is outputting 5V, which is a potential difference between its output pin and its ground line.

Arduino relay module is used to control high voltage appliances with Arduino. If you have relays with lesser coil resistance so the current required for relay is more then you can add a pull up resistor to the arduino pin. Reply If you use pullup resistor you can use the above I realized that I have not connected the arduino ground to the battery ground. BUT we dont know at which height the tanks are..so if you just connect their bottoms together we could potentialy blow them up imagine if one tank with 3m in it is lets say 1km up on a mountain and the other tank with 9m of water in it is at sea level. Thanks for posting this--it's a huge help for beginners like me.I've been researching on connecting relays to the Arduino and all of the examples I found either used a separate power supply for the 12-Volt relay (using a 9-volt battery) and the Arduino (using a USB cable) OR, the Arduino board itself supplies the power but the relay is only 5 Volts.If I may ask, would it be possible to use only 1 power supply for the Arduino (via the DC crown jack) and three (3) 12-Volt relays (only 1 relay will operate at a given time)?

To connect a 12V relay to the Arduino you need the following things: - 1 Arduino - 1 diode for example 1N4007 - 1 NPN transistor for example 2N2222 (in the US) or BC548 (in Europe) - 1 relay for example one with coil voltage 12V and switching voltage 125VAC/10 A - 1 multimeter Your relay needs a potential difference of 5V on its input line relative to its ground line in order to trigger. Datasheet for it gives the same hfe value of 75 @ 10ma @ 10v.

That's the bare minimum that is needed for the relay … Checked all connections, could the transistor be at fault here ? Youngneer 12v Relay Board Raspberry Arduino Relay Module 1 Channel Opto-Isolated High or Low Level Trigger.

Answer An arduino can only supply so much current, usually around 20mA, enough to drive an LED. 3 years ago

NOYITO 4-Channel Relay Module DC 5V 12V 24V Self-locking Triggering Interlocking High Low Level Trigger for PLC Industrial Control Arduino (5V) 4.5 out of 5 stars 2 $13.99 $ 13 . A pull up resistor is basically a resistor between the controller pin and the Vcc. Any circuit that needs more than 20mA will need some sort of current amplifier or buffer hence the transistor. The 0.7V doesn't make much difference. if you join their bottoms the flow would be so high that would crash the bottom tank!! If you used a 12V relay like we used in this project Arduino Relay Control, you need to use a separate power supply for relay. The PIN's are correctly detailed on the diagram, your problem aren't the PIN's, your problem is that you don't know how to read de diagram to do the correct connections.Only 3 PIN's to be connected, and only 1 goes to Arduino, the Digital Port 13, the rest of the PIN's was connected like the blue connectors on this video: https://www.youtube.com/watch?v=S-QddCWt5l4 12v * 0.75 = 9v. I want to use my arduino to latch on a relay. But then I was really confused. can we connect the output pin directly to relay?