SOLVED - PWM interchangeable with Variable Resistor?

Thread Starter

montag1138

Joined Aug 28, 2021
30
There is a board I'm thinking of purchasing which says it can accept input from either PWM or a variable resistor (diagram included below.)

There are other boards which are much less expensive which have the same inputs. How likely is it that the below diagram will work with these other boards?

Thanks in advance.
WIRING-RESISTOR.jpg
 

MrAl

Joined Jun 17, 2014
11,587
There is a board I'm thinking of purchasing which says it can accept input from either PWM or a variable resistor (diagram included below.)

There are other boards which are much less expensive which have the same inputs. How likely is it that the below diagram will work with these other boards?

Thanks in advance.
View attachment 319758
There's no way to know if a pot will work with the other boards unless we can see the data sheet or at least the advertisement that you saw for the other boards.
You may even have to contact the seller in some cases to find out if it can handle a potentiometer.
 

Thread Starter

montag1138

Joined Aug 28, 2021
30
There's no way to know if a pot will work with the other boards unless we can see the data sheet or at least the advertisement that you saw for the other boards.
You may even have to contact the seller in some cases to find out if it can handle a potentiometer.
I was just checking to see if it might be just that easy to substitute a potentiometer, but since it requires additional circuitry, it isn't as easy as I'd hoped. No need to link to the other boards, I can just contact the sellers. But probably BobTPM is right; if it doesn't say it's compatible with a pot, it probably isn't.

Thanks everyone for your insight!

I have seen room deviders and patricians but never saw a voltage devider? I have seen voltage dividers. The image in the first post references a "voltage devider". :)

Ron
Yeah he's from Latvia :)
 

Thread Starter

montag1138

Joined Aug 28, 2021
30
First, the potentiometer IS A VOLTAGE DIVIDER!!
Voltage dividers are not important to the discussion; it was a humorous observation if you had looked at the diagram.
and second we do noteven know what "works" means in thhis instance.
What the circuit does is not important to my question, but post #4 answers your question. I wasn't asking about a specific circuit, I was asking about PWM input in general, and my question has already been answered in post #2.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
19,049
OK, I followed that link and eventually saw some specifications for that assembly.
First, that is a reasonable price for a dimmer with an 8 amp rating. In fact, that is a good price for it.

Second, being able to utilize either PWM or a variable resistance from a potentiometer is not at all common for such a controller. In fact, this is the first I have seen with dual capability at the same terminal. So it appears to be a rare find.
 

Thread Starter

montag1138

Joined Aug 28, 2021
30
First, that is a reasonable price for a dimmer with an 8 amp rating. In fact, that is a good price for it.
I know, right! I'll be interested to see if it can actually handle 6-7A for an extended period. It's exactly what I need at a decent price. Building my own circuit would cost me probably near $200 and I can't justify that spend for a dimmer. Plus I haven't been able to find several of the parts I'd need to do it. (I don't know enough to substitute parts).
 

MrAl

Joined Jun 17, 2014
11,587
I know, right! I'll be interested to see if it can actually handle 6-7A for an extended period. It's exactly what I need at a decent price. Building my own circuit would cost me probably near $200 and I can't justify that spend for a dimmer. Plus I haven't been able to find several of the parts I'd need to do it. (I don't know enough to substitute parts).
You mean this is just an ordinary dimmer circuit with a pot to control the output and an output current rating of 8 amps?
You could build one for under $20 USD (in parts). You could even use a 15 amp triac instead of say a 10 amp triac and be reasonably sure it will work for a long time.
 

Thread Starter

montag1138

Joined Aug 28, 2021
30
You mean this is just an ordinary dimmer circuit with a pot to control the output and an output current rating of 8 amps?
You could build one for under $20 USD (in parts). You could even use a 15 amp triac instead of say a 10 amp triac and be reasonably sure it will work for a long time.
This board can control both incandescent and dimmable LED bulbs, as well as accept both PWM and pot input to control the dimmer; can a device be built to do this for around $20? The company selling it is obviously making a profit in bulk even at $15, but on one hand this is already built for $24 including shipping. I enjoy building and learning, but sometimes I'll just go for convenience!

On the other hand there are many circuits out there but they all seem to only work with incandescent bulbs. I priced three different schematics for circuits which handle incandescent-only output, and potentiometer-only input, and they came out closer to $100-$150 in parts. This is partly because some of the parts are discontinued, and since I'm still learning I don't know enough to choose substitutes.

My other thought is that maybe a standard store-bought wall-mounted dimmer switch might work if I'm just going to use variable resistance to control the dimmer. (But this is a bigger discussion for another thread for a very specific application.)
 

MrAl

Joined Jun 17, 2014
11,587
This board can control both incandescent and dimmable LED bulbs, as well as accept both PWM and pot input to control the dimmer; can a device be built to do this for around $20? The company selling it is obviously making a profit in bulk even at $15, but on one hand this is already built for $24 including shipping. I enjoy building and learning, but sometimes I'll just go for convenience!

On the other hand there are many circuits out there but they all seem to only work with incandescent bulbs. I priced three different schematics for circuits which handle incandescent-only output, and potentiometer-only input, and they came out closer to $100-$150 in parts. This is partly because some of the parts are discontinued, and since I'm still learning I don't know enough to choose substitutes.

My other thought is that maybe a standard store-bought wall-mounted dimmer switch might work if I'm just going to use variable resistance to control the dimmer. (But this is a bigger discussion for another thread for a very specific application.)
Hi,

Well I quoted $20 USD because you often can not buy just one resistor for 5 cents (USD) you have to buy a whole pack so that could run into $10 for resistors or something like that. Per unit though, it could be much less. 50 cents for an IC chip, a few resistors, some cheap common diodes, the highest cost would be the triac.

But if you are getting them for $24 already built, then maybe just go with that unless you need a lot of them, then consider building the circuit yourself, but you might also need a case so that could be another $5 or something. I thought you were paying a lot more for one as you made it sound like it was very expensive.

The circuit I was talking about uses a potentiometer, not PWM, because that is what you said you needed.
If you are into microcontrollers though you can do a lot with them at low cost.
The incandescent bulb type dimmers are probably old style so you probably do not want them.
 

Thread Starter

montag1138

Joined Aug 28, 2021
30
I thought you were paying a lot more for one as you made it sound like it was very expensive.
Well, in today's economy $24 is a lot lol
The circuit I was talking about uses a potentiometer, not PWM, because that is what you said you needed.
If you are into microcontrollers though you can do a lot with them at low cost.
The incandescent bulb type dimmers are probably old style so you probably do not want them.
Yeah I need a variable resistor, but the option for PWM would be nice in the future. However I do need to control both dimmable LED bulbs and incandescent bulbs. I ordered this card, and I do need to make a few more of these so maybe I can build my own cards or find a circuit online which meets the requirements. Thanks for your input!
 

MrAl

Joined Jun 17, 2014
11,587
Well, in today's economy $24 is a lot lol

Yeah I need a variable resistor, but the option for PWM would be nice in the future. However I do need to control both dimmable LED bulbs and incandescent bulbs. I ordered this card, and I do need to make a few more of these so maybe I can build my own cards or find a circuit online which meets the requirements. Thanks for your input!
Oh ok yes, so if you only need 1 unit then building your own probably won't save anything.
 
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