Re: The Transconductance of FETs

[Fred Townsend]

Declan Moriarty wrote: Recently, Somebody Somewhere wrote these words This question arose because in my particular niche, speed is everything. Speed of response to your customer or speed of the switching circuit? I fail to see the relevance to either in this discussion. Speed of response to the customer. It isn't a technical issue, but technical issues aren't the only consideration. Speed of response is also. In small outfits, only one machine of each type may be running. I fixed a drive which had been vandalised (Somebody kicked it repeatedly!) yesterday. They were ringing around getting prices for bringing production to competitors to have them finish it, and would be doing it today, except they are going again. We may be a third of a world apart but line stoppages are stoppages the world over. Be glad you are working in a 'Just-In-Time' plant.  Unfortunately if it is not a technical issue then I can only offer my sympathy. I found myself trying to find a logic level fet in the stock of a supplier who didn't discriminate between logic level fets, and less sensitive ones, and wondered if could the gfs be extrapolated into a reckoning of the saturation voltage. That's worth knowing if I could do it. I sense you have mis-characterized the problem. Are you dealing with a former tube (valve) distributor that now sells a universal semiconductor line? Without naming names, these lines purport to substitute for many of the OEM lines. They give only vague, mostly useless specifications. If so would suggest you switch to an OEM distributor but you probably knew that. These guys are ones you 'know fairly well on a personal basis'. How is the coffee or tea at their place? Sounds like a social issue, not a technical issue. Fred Townsend No, I'm not dealing with such a company. I'm dealing with a company who sold semis for years, tried dabbling in valves, and stopped afaict. BTW, they don't serve coffee. Is it tea then or perhaps it's Guinness? Ay don't we both wish. Ireland is a small place. Dealers are numerous, but dealers with stock are rare. If I had the same work coming, I'd stock myself. But I get boards designed in Germany, Italy, Japan and the Far East, Sweden, England and other places (Those are the main sources). It's not practical to stock, or find the same part numbers and wait for them to arrive. Ok we have resolved this is not purely a technical issue. Hopefully our host will indulge this way OT discussion a bit longer. I must admit my knowledge of the Irish Semiconductor Industry is limited getting 2N3392s and diodes out of the GE fab decades ago.  If the 'Dealers are numerous, but dealers with stock are rare' what does the dealer do for you except to take your order? Seemingly if order taking was the only issue then getting on the Internet and letting people like Jaap help you out would cut out the middle man. Are there import issues I don't see here? The 'guys I know fairly well' reccomend me to their clientele as a problem solver and that's worth a bit in a small fishbowl of an economy. OK now I understand it's not about FETs it's about advertising your services. Fred Townsend