will this solenoid swap work

I would like to use this attached circuit for my solenoid of 24V, 33ohm, and 727 mA specs.

  • see attached pic

V1 will be 24V
V2 will be 12V
Vcc will be 5V

Control Input Signal will be a control signal from Arduino.

The only worry is that the original solenoid that I’m replacing had a much lower power rating. Can someone tell me if my new solenoid will work in this circuit? Or will the power be too much? New solenoid is 17 watts from Ohm’s Law. The original was around 0.78 watts.

This is the webpage :

http://www.theleeco.com/engineering...e-solenoid-valve-drive-circuit-schematics.cfm

Thank you for the advice.

Hmmm. 47 times the power. Not likely. Does that not seem like a stretch to you?

The transistors are rated to a max of 15A. The relay draws about 3A. It may work.

If you are using an Arduino to run this, why use the 555? The Arduino can do its function.

With a quick look at the circuit, I think it probably can be done simpler with a bit of thinking.

Weedpharma

Why not use a logic mosfet and PWM. Leo..

Hi, Weedpharma. I didn’t want to code the Arduino, because I want this setup hard wired, so no one can change the code by mistake. Also it may be switched out and not used with the Arduino at times. For now I would just like the Arduino to switch it on and off only. I would still like to try to use this circuit.

The transistors sound good. Which part is the 3A draw? What else can I check to make sure this works?

Thanks!

Are you saying my new solenoid (relay) will draw 3A? Isn't the max .72727 A? The highest voltage is 24V and it is 33 ohm. Can you clarify?

What about the diode ratings? Thoughts on those? Thanks! Enjoy your Sunday.

The only worry is that the original solenoid that I'm replacing had a much lower power rating. Can someone tell me if my new solenoid will work in this circuit? Or will the power be too much? New solenoid is 37 watts from Ohm's Law. The original was around 0.78 watts.

You stated the solenoid is 37w. I worked out current with 12v but now realise it should have been 24v, so still 1.5 A. You had not given the R at that time.

Weedpharma

that original 37 watt should say 17. sorry, i typed wrong.

this is what i get now:

24V , 33 ohms, and 727 mA.

Ohms Law : V = I × R and P = I × V

24V = I x 33 therefore I = 0.72727 A 12V = I x 33 therefore I = 0.36364 A

P = 0.72727 x 24 = 17.45 watts P= 0.36364 x 12 = 4.36 watts

http://www.ohmslawcalculator.com/ohms-law-calculator

i'm thinking the transistors and diodes can handle those ratings. let me know if not.

thanks!

That sounds ok to me.

Weedpharma