LED strip with B10K pot and blinks if resistance is high

Hello, I have simple circuit. 12V power. LED strip is connected to power via B10K potentiometer. Everything works fine until resistance is too high. Then LED strip start blink. https://goo.gl/photos/JjJdJLGeeRDMXD2j9

If potentiometer is on min, there is about 10V voltage. If potentiometer is on max, there is abou 7V voltage.

Can you explain me what happens and how to avoid this blinking, if resistance is high?

You were asked to post a schematic here.

Without (a lot) more information, it's impossible to answer this question.

How long is your LED strip (how many LEDs) and what type (white/RGB).
What is the current rating of your 12volt supply.
How did you connect the 10k pot, the mosfet, and where is your code.

fenak:
If potentiometer is on min, there is about 10V voltage. If potentiometer is on max, there is abou 7V voltage.

The Arduino outputs PWM. Not a "voltage".
Impossible to measure correctly with a DMM.
Leo..

I tried it with 30 cm rgb strip and with 5 m white strip (is on the video). Supply is 12V 2A. For now the circuit is without Arduino. Just potentiometer, strip and power supply. Gnd is connected to strips gnd, vcc is connected to pot and regulated voltage to strips vcc.

A 5 meter white strip (assuming 30 white LEDs per meter) could use 53020mA= 3Amp.
A 2Amp supply is not enough.

It COULD be that the (unknown) supply is getting in/out of current protection.
Even with dimmed LEDs there are full (3Amp?) current spikes, because PWM turns the strip fully on/fully off (many times per second).
IF...the supply is "pumping", then a (470-1000uF) electrolytic capacitor across the supply (at the LED strip) could help.

fenak:
For now the circuit is without Arduino. Just potentiometer, strip and power supply.

Do you mean the pot is driving the mosfet gate?
A mosfet used like this (no PWM) could get stinking hot in seconds, and burn out.
A pot alone (no mosfet) would burn out instantly.
Be specific. Post diagrams.
Leo..

Just make a drawing with pencil, scan it or take a photo of it and post it here.

Hi

Can you tell us your electronics, programming, arduino, hardware experience?
Do you understand Ohms Law and the principle of current limit resistors for LEDs?

What you want to do with the LED strip?

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Thanks.. Tom.. :slight_smile:

It is strip with 300 LEDs on 5 meters: http://www.banggood.com/5M-White-3528-SMD-LED-Strip-Light-Non-Waterproof-12V-DC-300-LED-p-77079.html

I want use it with some clon of arduino but working on 3.3V and now I’m waiting to mosfet IRLZ44N. Until it arrives I want to change brightness manually by potentiometer.

10k-pot-and-led-strip.jpg

That's just a single LED connected to a pot as voltage divider. Not the best way to drive a led... And I don't have a clue what it has to do with led strips and mosfets...

Hi,
Okay, just don't go putting that pot in series with the strip and power supply, you will burn out the end of the pot and it will be useless.

Can you tell us your electronics, programming, arduino, hardware experience?

Specs from Banggood.

Description:
Item: Strip (White)
Non-Wterproof: IP 44 (For indoor use only)
LED Chip: SMD 3528
Viewing Angle: 120°
Length: 5000mm
Width: 8mm
Input Voltage: 12V DC
Power: 2A 24W
LED Quantity: 60pcs/Meter, 300LEDs in total
Luminous Flux: 840lm/Meter
Color: White

Thanks.. Tom... :slight_smile:

It is really LED strip. Picture shows single LED because in image library is no LED strip.

Finnaly (with mosfet) it should be wired like in attachment.

fenak:
It is really LED strip. Picture shows single LED because in image library is no LED strip.

That's why a hand dwawing is wayyyyyy beter. Especially compaired to a stupid Fritzing "diagram" (because it certainly isn't a circuit

fenak:
Finnaly (with mosfet) it should be wired like in attachment.

Still don't have a clue what the mosfet and pot have to do with each other..

But that will definitely not work. Or yeah, it will light up the led just fine. Because if you follow the wires the led is with both + and - connected to the power supply directly...

It should be the same like on Jerome Bernard: RGB Led Strip controlled by an Arduino but no RGB LED strip, just white LED strip (no 3 tranzistors, just one).

Edit: Oh, I see there should be a resistor between drain and power supply.

fenak:
It should be the same like on

Only thing is, it doesn't look anything like that.

Hint, not all mosfets have the same pinout :wink:

fenak:
Edit: Oh, I see there should be a resistor between drain and power supply.

Huh, why???