High power switching circuit problem.

In summary, the arduino pin output is controlling the gate of the mosfet, but when the arduino pin output is HIGH the LED turns on and when the arduino pin output is LOW the valve does not turn on.
  • #1
perplexabot
Gold Member
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Hello all. I am trying to use a mosfet as a high power switch. I have an arduino nano pin controlling the gate of the fet. I am using an NTE2374 mosfet. I am using a typical circuit:
img_1224968365_15332_1271040628_mod_483_350.jpg


I also have the gate connected to the source (ground) so that when the gate is not HIGH, it isn't floating.

I have been testing this circuit on two separate components; main component (the valve) and also on an LED (not sure if this is a good idea). I have found the following things to happen:
  • When the arduino pin output is LOW and the component is either a valve of LED, the
    component was off (as it should)
  • When the arduino pin output is HIGH the LED turns on.
  • When the arduino pin output is HIGH the valve does NOT turn on and the voltage reading on
    my dc power supply goes from 15V down to zero in a moment.
I have been at this for a couple of days and I can't seem to figure out what the problem is. Can anyone help me out or direct me towards the correct path? Thank you.
 
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  • #2
It sounds to me like the 'valve' as you call it which I assume is a solenoid valve draws more current than your power supply is able to source.
 
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  • #3
D1 could have failed by going short circuit.
The valve could have failed by going short circuit.
The wires to the valve and D1 may have been swapped, which forward biasses D1.
 
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  • #4
Averagesupernova said:
It sounds to me like the 'valve' as you call it which I assume is a solenoid valve draws more current than your power supply is able to source.
Yes, it is a solenoid valve. So, I tried increasing the current knob on my power supply and... it worked, LOL. Thank you. I hooked it up to my battery and it worked directly. I learned something new today: A dc power supply, by default, doesn't source current.

Thank you Averagesupernova and Baluncore for the quick replies.
 
  • #5
You maybe have the diode in backwards?
It's wired incorrectly?
The power supply is current limiting at too low a threshold?

What happens if you short across the FET to turn on the thingy.

The FET input capacitance is 1300pf so the turn on will be slow. During that switching time the FET dissipates a lot of power. But even if the FET blew, I don't see how that causes what you describe.

EDIT: Problem solved while I was typing
 
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  • #6
meBigGuy said:
...
:biggrin:
meBigGuy said:
The power supply is current limiting at too low a threshold?
You got it. Thanks anyway!
 
  • #7
perplexabot said:
So, I tried increasing the current knob on my power supply and... it worked, LOL.

I was wondering why the LED that you tested first didn't burn out with 12V applied to it. That would explain it :smile:

(But I didn't want to spoil everybody's fun guessing the answer by looking at ALL the evidence, so I didn't post this earlier!)
 
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  • #8
AlephZero said:
I was wondering why the LED that you tested first didn't burn out with 12V applied to it. That would explain it :smile:

Aahahaha, didn't even cross my mind. Lucky led.
 

Related to High power switching circuit problem.

1. What is a high power switching circuit?

A high power switching circuit is a type of circuit that is able to control the flow of electricity from a high power source to a load. It typically involves the use of transistors or other electronic components to switch the circuit on and off, allowing for precise control over the power flow.

2. What are the common problems associated with high power switching circuits?

Some common problems associated with high power switching circuits include overheating, voltage spikes, and electromagnetic interference (EMI). These issues can lead to malfunctions or damage to the circuit and its components.

3. How can I troubleshoot a high power switching circuit problem?

To troubleshoot a high power switching circuit problem, you can start by checking for loose connections, damaged components, or incorrect wiring. You can also use a multimeter to measure the voltage and current at different points in the circuit to identify any abnormalities.

4. How can I prevent damage to my high power switching circuit?

To prevent damage to your high power switching circuit, it is important to properly size and select components that can handle the power load. You can also use protective measures such as fuses or surge protectors to prevent voltage spikes. Regular maintenance and monitoring can also help identify any potential issues before they become major problems.

5. Are there any safety precautions I should take when working with high power switching circuits?

Yes, there are several safety precautions you should take when working with high power switching circuits. Always disconnect the power source before working on the circuit and wear protective gear such as gloves and safety glasses. Make sure to follow proper wiring and grounding techniques to prevent electric shock. It is also important to have a thorough understanding of the circuit and its components before attempting any repairs or modifications.

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