HarryA Posted March 31, 2017 Report Share Posted March 31, 2017 "50Pcs NPN Transistor TO-92 2N2222A 2N2222 Brand New Practical High Quality" (Ebay) Does "Practical High Quality" mean hfe's of almost 100 Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 1, 2017 Report Share Posted April 1, 2017 ebay means "manufacturer's rejects" and "sweepings off the floor". Don't buy anything from ebay, instead buy from a reputable and reliable Western electronics parts distributor. Haven't you see a datasheet of an old 2N2222 transistor? Like all transistors its hFE is a range of 1 to 3 times and the actual hFE also varies with the collector current. With a collector current of 1mA the minimum hFE is 50 with no guaranteed maximum hFE. With a collector current of 150mA the hFE is guaranteed to be from 100 to 300. hFE is DC current gain that is listed and shown on a graph on a datasheet. hfe is AC current gain that is usually a little less than hFE at low frequencies and is usually not shown on a datasheet. Quote Link to comment Share on other sites More sharing options...
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