Hi all. :D I have seen alot of circuits with a 7812 (12V regulator) with a PNP transistor for current bypass (or how you explain it).
I would really like MOSFET transistors instead om bipolar transistors.
How??? :?:
Tnx Johan in Karlskoga, Sweden. SM4YZN
Why? There's no particular advantage, in fact there's a big disadvantage- the dropout voltage will be quite a bit higher because of the higher "Vbe". That means more wasted heat.
Best regards, Spehro Pefhany
What do you 'like' about them then ?
It's not a suitable applcation for a mosfet actually for the reasons Spehro mentions. A bipolar is the way to go.
Graham
View in a fixed-width font such as Courier.
. . . . +-----------------------+ +-+-------+ . | | ^ | | . | ===== | . | | | . +-----e c----+---------+---[R2]--+ . | \\ / | | . | --+-- C1=== | . | | | | . | | | | . | | [R3] +--7812--+ | . | | | | | | . Vin>-+--[R1]-+-------+----+ +-----+-->Vout . | | . +---+----+ . | . | . gnd . . . .
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