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Thanks for your detailed response and also Thanks Harald. I will change TIP122. Can I use IRLZ34N? Logic MOSFET is enough for me. Can I use your circuit diagram with IRLZ34N? Are resistors values fine for IRLZ34N?If you choose MOSFET this would be circuit you would want to use :
View attachment 58050
The diode is to limit L transient that occurs due to MOSFET turn off. Protects
MOSFET from exceeding gate oxide rupture.
The R18 is to insure when micro starts up, and tristates its GPIO, the MOSFET
stays off, until processor code takes over.
The 220 ohms is to limit current spike that occurs when GPIO turns high, to prevent
disrupting processor internal buss from spiking low causing potential code erratic
operation. Note if you were driving with a PWM then the 220 ohm needs to be lowered
to insure MOSFET does not stay in its linear region too long. There are application
notes available to do that calculation. Typically that is more like 10 - 50 ohms.... Also
one would not use processor GPIO direct in that application, one would use a MOSFET
gate driver to handle the high currents driving the MOSFET input and Miller capacitance.
Regards, Dana.
I will not use pwm only digitalwrite functio. I only want to open and close motorYou driving MOSFET with a PWM ? If so this might help to calc the
gate R :
R18 fine as it is. The diode preferably wants to be a fast diode. 1N4148 for, depending on motor L.
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Can a Zener diode that protects a switch against inductance when the switch opens, affect turn on speed of the valve when you close it again?
As you probably know, in the applications that the turn off speed of the solenoid valves are crucial, the simple flyback diode is not effective. Some people put a resistor in series with the flybackelectronics.stackexchange.com
Regards
The device will need to handle the initial current, especially if a load is present at switch on.I
I will not use pwm only digitalwrite functio. I only want to open and close motor
If no PWM, The device will need to handle the initial current, especially if a load is present at switch on.
Then the 220 ohm in MOSFET gate should be fine.I
I will not use pwm only digitalwrite functio. I only want to open and close motor
Thanks everyone, As you sad dana I will use 1N4148 diode for motor L but is diode max current important? Is 450 mA forward diode current enough for my 2.5A motor?Then the 220 ohm in MOSFET gate should be fine.
If you have a scope look at turn off of motor, if you are still getting
high V spikes on MOSFET drain then consider adding this as well
in parallel with motor and diode, a snubber.
Regards, Dana.
Thanks for everything Dana. I am really glad about your incredible help. Sorry, I am a new maker sometimes I can be confused. I have a question about diode why can't I use only MBR560 diode? Why do I need a fast diode? I won't use pwm. Can you help me understand?Boy did I screwup, no that diode is not adequate.
Something like this :
Basically a 200 nS, 5A, 100V or better.....Note speed one normally tries a representative
diode, looks at scope on MOSFET turnoff, and examines pk transient V to make sure
that does not exceed MOSFET specs. Look at both drain and gate when doing it. So
200 nS a starting point.
Regards, Dana.
You have some good advice already. I would approach it like a Thevenin source and load impedance and find out what the values are or need to be for the supply, converter and load. In order to regulate torque with current and low loss the supply must be the lowest ESR, then the "switcher" must be a reasonable low % of the load.Hi, I want to switch 2 ampers 9V DC motor with TIP122 Transistor using Arduino nano. How many ohms resistor should I use for the transistor's base pin? How can I calculate? Thanks
Thanks for all your responses. You can see my final design I haven't tried it yet, But when I try I will share my feedback when I tested it. I want to sum up my applications for makers who want to use MOSFET. I wanted to switch a 2.5 Ampers 9V DC motor using Arduino nano most efficiently. Thanks, Maker Pro Forum.When the V reverses on the L (MOSFET turned off) it ramps very fast to a high V,
so diode needed to clamp it before its V gets too high, has to be fast. Thats the
reduced explanation as its complicated by the nature of the motor L, its losses,
and other considerations.
The MBR560 has no reverse recovery, Schottky's are normally much faster. But
datasheet has no specs so how fast it will switch has to be tested.
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Flyback diode - Wikipedia
en.wikipedia.org
View attachment 58099
Regards, Dana.