Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Comments on Is a BJT 3-transistor Wilson mirror faster than a simple mirror?

Post

Is a BJT 3-transistor Wilson mirror faster than a simple mirror?

+4
−0

My question is trying to understand if there is an effect on the switching time, on both turn-on and turn-off, between the following configurations.

A mirror set up to switch a current, and there is switching on the input side of the mirror input (for other reasons), meaning the simple mirror's base voltage must ramp up and down from near zero each time. In this configuration, is there a speed benefit to the 3-transistor Wilson mirror? Talking about discrete components, ~1 MHz switch freq.

image-1

image-2

History
Why does this post require attention from curators or moderators?
You might want to add some details to your flag.
Why should this post be closed?

1 comment thread

General comments (4 comments)
General comments
Olin Lathrop‭ wrote almost 4 years ago

We don't know what you think a "half-Wilson" mirror is. If you want to compare two circuits, show the schematics of both of them. Also the current would be a step, not "ramping" up and down. Do you mean the voltage ramps up and down to nearly both rails?

Pete W‭ wrote almost 4 years ago · edited almost 4 years ago

@Olin, sorry for not being more clear. Edited to hopefully clarify what I'm asking. I didn't mean that it is an intentionally controlled ramp, rather that the output (i.e. collector current sunk from the node at the top of the cap) takes measurable time to go from 0 to the value that it will have. I sort-of think the 3rd transistor would bring in extra current from the output side, but maybe this is offset by having another transistor to turn on, hence thought I would post the question.

Andy aka‭ wrote almost 4 years ago

Use a simulator. Really, use a simulator. If you are not able to use a simulator let me give you some very, very good and strong advice: Get a simulator and learn how to use it.

Pete W‭ wrote almost 4 years ago

@Andy aka -- yes, you are right. It's something I have been avoiding. Thanks for the push to get me there.