16-05-2017, 02:44 PM
Beta is the current gain. The ratio of collector current to base current. Emitter current is divided between the base and collector or another way of saying it is the emitter current is the sum of collector and base current and alpha is the emitter current minus base current. So beta should always be greater than one and alpha should always be lower than one.
If that make since then it would follow the ratios can be simplified by referencing a current of ONE. If Ie=1 then 1-alpha = base current. if I=1 then Ib = 1/beta.
I would recommend this book:
https://ia802607.us.archive.org/28/items...niques.pdf
Page 19 discusses current gain.
The diode vs transistor as a detector would probably be more an economics question. The manufacturer would but in bulk and get great pricing. If they used a 100 transistor for every diode the difference in cost would make using the transistor as a diode more cost effective. You can buy a JFET for 3 dollars each at dealer A or 2 cents each minimum of 1000 at dealer B. Someone will argue an operation advantage and it may be true but my take on it it economics drives business more than performance.
73
If that make since then it would follow the ratios can be simplified by referencing a current of ONE. If Ie=1 then 1-alpha = base current. if I=1 then Ib = 1/beta.
I would recommend this book:
https://ia802607.us.archive.org/28/items...niques.pdf
Page 19 discusses current gain.
The diode vs transistor as a detector would probably be more an economics question. The manufacturer would but in bulk and get great pricing. If they used a 100 transistor for every diode the difference in cost would make using the transistor as a diode more cost effective. You can buy a JFET for 3 dollars each at dealer A or 2 cents each minimum of 1000 at dealer B. Someone will argue an operation advantage and it may be true but my take on it it economics drives business more than performance.
73
