I designed a circuit. It is a PWM thing, four outputs not super high curren t. Open drain.
We got an oscillator, thing to make a triangle wave for the PWM, four compa rators for the out put, and no filtering at all and in fact that is EXACTLY what is needed.
About 40 components, three dual OP AMPs, four power MOSFETs, the rest elche apo resistors n shit.
I got more time into it than most of you would, but I am not after a rate. I wonder just what is fair for this. How much ? I got probably over 15 hour s in it not including doing the BOM. There have been four revisions, but on ly one was impelled by the customer.
Now this circuit is custom, and not complicated. There is no owning it.
Yes. I mean like both. I was thinking that I don't want to actually sell th e design, who knows if I use it again. But if I don't use it again... Can't be free.
The building and testing get underway when the parts get here. Te whole thi ng may slow down because the guy is now on chemo. The prognosis is good tho ugh and they only have him down for seven weeks of treatment. Of course he might not feel like doing anything during that time.
There are some predrilled boards I got my eye on for construction. Like fiv e bucks each, and there are two units. Parts probably fifty bucks each give or take.
the design, who knows if I use it again. But if I don't use it again... Can 't be free.
hing may slow down because the guy is now on chemo. The prognosis is good t hough and they only have him down for seven weeks of treatment. Of course h e might not feel like doing anything during that time.
ive bucks each, and there are two units. Parts probably fifty bucks each gi ve or take.
It was a long time ago someone pointed out to me the difference between cos t and price. Cost is based on what you are willing to pay to have a unit m ade. Price is based on what someone is willing to pay for your product. O ther than needing price to be more than cost to make the endeavor profitabl e, the two are not connected.
I've always used to factor of 2 rule of thumb to set the base selling price . Once there I adjust upward to allow adequate incentive for me to continu e producing units over time. Making a pittance gets old unless the volumes are very high.
I am not unfamiliar with cost and price. In fact I am about to hijack my th read here. Many years ago I read this;
"American car manufacturers used cost driven pricing, while foreign car mak ers used price driven costing"
I think you understand what that means. With the former, they tell manageme nt how much it is going to cost, with the latter it is the other way around . Like "You will do this at this price, find a way". And they did.
Anyway the expected sales volume is nil, this is a two off. I might be able to move a few more if I can get access to the right market but I am not ho lding my breath. And even then, couple units here and there. Not worth an e tch really.
Construction is going to be on boards that actually emulate a breadboard, b ut you can cut the traces for more flexibility and to get rid of stray capa citance. I think I can do it on the five buck ones. I saw them at Jameco, b ut I am sure there are other companies. I probably won't feel like shopping and five buck isn't bad so that is probably what it will be.
One thing that might help them move is the added capacity, they are overbui lt. I expect 5 amps, it'll handle 20. I expect 14 volts, it'll handle at le ast 50. The frequency is so low there is no reason for deration at all. Out put devices will be fully saturated or cutoff. I got low Rdson and a pretty high Vdsmax.
(is saturated technically the right term for a MOSFET turned fully on ? Wit h bipolar it means the Vbe exceeds the Vce, a MOSFET is a different animal, is there a different term for this state ?)
I probably got 15 hours in the design, you pros would have it done in half that. If I charged time, what should that be ? I mean you can't go lasso th e guy at McD's and have him do it, but it also isn't rocket science. (I got a dude for that believe it or not)
the design, who knows if I use it again. But if I don't use it again... Can 't be free.
hing may slow down because the guy is now on chemo. The prognosis is good t hough and they only have him down for seven weeks of treatment. Of course h e might not feel like doing anything during that time.
ive bucks each, and there are two units. Parts probably fifty bucks each gi ve or take.
Suggest you either charge a lot or give it away for free. No inbetweens.
There are simpler circuits possible, and of course you can add FETs and drivers as needed.
Maybe it's not actually PWM, just that it does that in the course of doing something else more important, like controlling inductor current. In that case, you'd want an op-amp or two around this.
We got an oscillator, thing to make a triangle wave for the PWM, four comparators for the out put, and no filtering at all and in fact that is EXACTLY what is needed.
About 40 components, three dual OP AMPs, four power MOSFETs, the rest elcheapo resistors n shit.
I got more time into it than most of you would, but I am not after a rate. I wonder just what is fair for this. How much ? I got probably over 15 hours in it not including doing the BOM. There have been four revisions, but only one was impelled by the customer.
Now this circuit is custom, and not complicated. There is no owning it.
What's fair is ideally you find someone else who needs something similar tell them "Yeah, I think I can come up with something that fits the requirements...", negotiate a price for the work, and then do what mods you need to for their application and send them the revised schematic and BOM and get paid again.
You can't own or "copyright" a circuit design but even if it's not patented you don't _have_ to release the plans to anyone you don't want to and particularly not if they're willing to pay for them. And you're certainly free to copyright the schematic diagram itself.
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