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- Опубликовано: 5 фев 2025
- Teardown of the cheap LED PWM dimmer - and some fun with oscilloscope measurements.
Scope used: OWON VDS1022i
This item came from HiLetgo on Amazon:
HiLetgo website:
www.hiletgo.com
United States Amazon Store link:
amzn.to/2Kkpfsg
Europe Amazon Store link:
amzn.to/2L5ink2
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Great pragmatic explanation of a commercial application for beginners (speaking as a long-time beginner 😉)
An excellent review and demonstration! So glad you got rid of the awful music you sometimes had. Two thumbs up!
I really like this circuit. It is a textbook example of an analog PWM circuit and perfect for teaching how one of the modes of an opamp (and the NE555) work. I'm also surprised by the non-jankyness of the components and general build quality.
Enjoyed your video. Best wishes from Northern Ireland.
Thanks!
Beautiful explanation
Thanks for this, well done. Any idea what the specs would be on that pot? Mine isn't working well, sometimes it doesn't turn all the way off, I'd like to try a different potentiometer.
Really nice, man. 😊
The best part is that there's no flickering in the light!
This runs at 1.3kHz, (I think I forgot to mention in the video) so the flicker was not visible to camera recording at 50 FPS.
@@randomtronic Exactly!
@@randomtronic - Excellent! I would like to build a camera light. For 2 led strips, 1 WW and 1 CW, I would like to build something with these dimmers, where one knob controls brightness and one knob controls colour temperature, without changing overall brightness. What is the smartest way to do it?
I thought of having: Battery => 1 dimmer for brightness => split to two dimmers, where I use a 1K stereo potentiometer instead of the 2 individual original 1K potis of the 2 dimmers, in order to "dim" between the two strips of different colour temperature. I hope you can follow me.
And can I save a wire to and from the led strips, by combinig the (+) of the two strips and have 2 separate grounds (-)?
Is there a smarter way to do it? Thank you very much for your help.
@@thekaiser4333 ruclips.net/video/DhbMnQt14_o/видео.html
@@mkingkral - Dear Martin, thank you. I wrote:
"I would like to build something with these dimmers, where one knob controls brightness and one knob controls colour temperature, without changing overall brightness."
I can't find the relavant bit in the link you sent me. Could you give me the timestamp of the relevant bit? I only find, where each strip is controlled individually.
Thank you.
Cool video🤘
Keep going, great.
Nice video/good explanation! And the device doesn't look that bad considering it can be bought for 2 bucks on eBay :)
Yep, surprisingly not junky. And one would struggle to put this together for less with the case and the knob included.
Does such simple dimmer:
1. Take current from the driver in pulsating way (full load current on PWM's "highs" and 0 current on PWM's "downs")?
or
2. Take constant stable current that is equal to the real mean consumption?
If the answer is 1: should I expect overcurrent caused by no-load periods occuring? E.g. 30V instead of 24V on driver
If I know, the dimmer will be set to 40% forever, should I buy a driver for 40% of load or I need to buy with 100% Watts to keep the signal stable?
Thank you for your video. I love your curiousity
And willingness to test out how things operate.
A question: i would like to use this approach to modulate leds internal to a capacitor switch.
Schurter 3-101-404
The leds are internally powered by (i am guessing)
A 3.3 v constant current supply. To turn them on i have to ground the pin connected to the led.
I was thinking of using the pwm between the led and the ground (when i turn it on)
Is that possible?
why cant i get this to dim my LED deck lights? I ordered the lights from amazon : recessed LED Deck Light Kits from SMY Lighting Store
what if want to make it smart, connect an ESP8266 and control dimming via WIFI? what settings/PWM signals should I use and which pin ?
Does this dimmer consume electricity when its "dimmed" all the way to the lowest setting? Or is it completely off?
I guess my question is: Does this dimmer consume more electricity (when turned all the way to off) compared to a ordinary on/off switch in off state (which consumes 0 amps since the circuit is open)?
This is probably the most stupid question you'll get for this video but... what is the output voltage and current of this device if I supply it with a 12V/7A battery? Does this device have any significant resistance value? thanks.
This outputs same voltage as input (12V-24V is the acceptable range) modulated PWM - that's how it adjusts the output: Pulse Width Modulation. Look it up, you'll get it. And yes, you can connect it to 12V battery to be able, for example, dim some 12V lights.
@@randomtronic thanks!
It's a waste to have a 555 and an op-amp when the other unused op-amp could have been easily used as a triangle wave generator!
Creating a DC triangle wave requires two op-amps, so it would use both halves of an LM358,. Even so, they could have used an LM324 quad op-amp, which costs the same as the LM358. The same number of passives are required, so the cost would have gone down by deleting the 555. Good idea, Ed.
@@FlyingShotsman yes, for a pure triangle wave, but you can tap off of the capacitor from a simple relaxation oscillator to get a triangle wave with exponential ramps just like the 555.
I thought that too - it could be done with a simpler circuit and 1 IC only.