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Started by Unknown February 16, 2019
I designed a circuit. It is a PWM thing, four outputs not super high current. Open drain. 

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 is fair ?
On 17-Feb-19 10:35 AM, jurb6006@gmail.com wrote:
> I designed a circuit. It is a PWM thing, four outputs not super high current. Open drain. > > 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 is fair ? >
Do you mean how much to sell the design to your customer or how much per unit assembled & tested?
On 02/16/2019 06:35 PM, jurb6006@gmail.com wrote:
> I designed a circuit.
...
> There have been four revisions, but only one was impelled by the > customer.
Impelled! That's acceptable, I guess.
>"Do you mean how much to sell the design to your customer or how much per unit assembled & tested? "
Yes. I mean like both. I was thinking that I don't want to actually sell the 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 thing may slow down because the guy is now on chemo. The prognosis is good though 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 five bucks each, and there are two units. Parts probably fifty bucks each give or take.
On Sunday, February 17, 2019 at 10:53:35 AM UTC-5, jurb...@gmail.com wrote:
> >"Do you mean how much to sell the design to your customer or how much per unit assembled & tested? " > > Yes. I mean like both. I was thinking that I don't want to actually sell the 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 thing may slow down because the guy is now on chemo. The prognosis is good though 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 five bucks each, and there are two units. Parts probably fifty bucks each give or take.
It was a long time ago someone pointed out to me the difference between cost and price. Cost is based on what you are willing to pay to have a unit made. Price is based on what someone is willing to pay for your product. Other than needing price to be more than cost to make the endeavor profitable, 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 continue producing units over time. Making a pittance gets old unless the volumes are very high. What do you expect the sales volume to be like? Rick C.
On Sat, 16 Feb 2019 18:35:51 -0800 (PST), jurb6006@gmail.com wrote:

>I designed a circuit. It is a PWM thing, four outputs not super high current. Open drain. > >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.
Doesn't using that cause leakage? -- John Larkin Highland Technology, Inc lunatic fringe electronics
>"What do you expect the sales volume to be like? "
I am not unfamiliar with cost and price. In fact I am about to hijack my thread here. Many years ago I read this; "American car manufacturers used cost driven pricing, while foreign car makers used price driven costing" I think you understand what that means. With the former, they tell management 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 holding my breath. And even then, couple units here and there. Not worth an etch really. Construction is going to be on boards that actually emulate a breadboard, but you can cut the traces for more flexibility and to get rid of stray capacitance. I think I can do it on the five buck ones. I saw them at Jameco, but 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 overbuilt. I expect 5 amps, it'll handle 20. I expect 14 volts, it'll handle at least 50. The frequency is so low there is no reason for deration at all. Output 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 ? With 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 the 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) Thus my queries.
>"Doesn't using that cause leakage? "
Why would it ? Please clarify.
jurb6006@gmail.com wrote...
> >> "Doesn't using that cause leakage? " > > Why would it ? Please clarify.
"elcheapo resistors n shit" Most of the experienced engineers here will suspect adding shit causes leakage, but you can check and see. -- Thanks, - Win
>"Most of the experienced engineers here will suspect
adding shit causes leakage, but you can check and see. " Maybe I mis expressed (?). There are no extra components in it. Throw me an email without the at sign and I'll send it to you. I just have nowhere to host it right now.