Arduino Forum

Using Arduino => General Electronics => Topic started by: endrithoxha123 on Jun 30, 2020, 06:03 pm

Title: Arduino 12v PWM
Post by: endrithoxha123 on Jun 30, 2020, 06:03 pm
Hello
I need to control a vacuum valve in the car with arduino, depending on the rpm, duty cycle is from 40% -75% (pwm), what transistor should I use and if anyone can help me with the scheme, the valve voltage is 12v
Thanks
Title: Re: Arduino 12v PWM
Post by: Ron_Blain on Jun 30, 2020, 06:22 pm
You make no mention of the load current making it impossible to suggest a transistor. Low current a 2N3904 good to about 200 mA, the 2N2222 is nice to 800 mA and personally rather than a transistor I like the FQP30N06L or for light work a 2N7000. The latter two are MOSFETs. So how about you provide a drawing of your intended application and some real world numbers?

Ron
Title: Re: Arduino 12v PWM
Post by: endrithoxha123 on Jun 30, 2020, 06:39 pm
measured, the current is about 1.1A,
while the sensor has two terminals positive and negative
Thanks
Title: Re: Arduino 12v PWM
Post by: endrithoxha123 on Jun 30, 2020, 07:04 pm
I upload image in this link because i cant upload here

https://ibb.co/6XvgqJN
Title: Re: Arduino 12v PWM
Post by: MarkT on Jun 30, 2020, 08:46 pm
You current is flowing the wrong way!

For over an amp a logic-level MOSFET is appropriate, rated at 55V (standard automotive voltage), 0.1 ohm or less on-resistance.

You need to common the grounds between the switched circuit and the Arduino.  The valve will be inductive so
a free-wheel diode is needed across it - as in circuits for switching a relay using a mosfet.
Title: Re: Arduino 12v PWM
Post by: endrithoxha123 on Jun 30, 2020, 09:53 pm
but relays do not work here, because the valve will operate with pwm signal with source voltage 12 volt
Title: Re: Arduino 12v PWM
Post by: Ron_Blain on Jun 30, 2020, 10:01 pm
but relays do not work here, because the valve will operate with pwm signal with source voltage 12 volt
Quote
The valve will be inductive so a free-wheel diode is needed across it - as in circuits for switching a relay using a mosfet.
As in a circuit for switching a relay. Read what was posted.

You want a Logic Level MOSFET and you can PWM the low side of the valve. It's a common circuit, nothing unique or out of the ordinary.

Ron
Title: Re: Arduino 12v PWM
Post by: endrithoxha123 on Jun 30, 2020, 10:09 pm
As in a circuit for switching a relay. Read what was posted.

You want a Logic Level MOSFET and you can PWM the low side of the valve. It's a common circuit, nothing unique or out of the ordinary.

Ron
Sorry , I apologize for my mistake, thank you for your help

All the best
Title: Re: Arduino 12v PWM
Post by: TomGeorge on Jul 01, 2020, 04:06 pm
measured, the current is about 1.1A,
while the sensor has two terminals positive and negative
Thanks
What sensor?
Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html (http://forum.arduino.cc/index.php/topic,148850.0.html).

Thanks.. Tom... :)