Hi.
I studied electronics 13 years ago and haven't done it since. I have a schematic below which I know is wrong I just don't know how to make it right. I am also hoping you fine peeps can tell me what each components value should be. This is a once off project and would take days to figure it out by myself.
The purpose is to run a fan from 10-60 seconds once power is applied then stop. I would also like to be able to vary the speed of the fan. The fan is a small 80mm computer case type fan. Not sure what the current draw is but can test if needed.
I know the problem with my schematic is the fan will be off until the RC turns on the base so I've actually created the opposite of what I need. I also am guessing VR1 would be better at the base of the transister?
**broken link removed**
I am a noob and this is my first post. Your help would be hugely appreciated. Many thanks.
I studied electronics 13 years ago and haven't done it since. I have a schematic below which I know is wrong I just don't know how to make it right. I am also hoping you fine peeps can tell me what each components value should be. This is a once off project and would take days to figure it out by myself.
The purpose is to run a fan from 10-60 seconds once power is applied then stop. I would also like to be able to vary the speed of the fan. The fan is a small 80mm computer case type fan. Not sure what the current draw is but can test if needed.
I know the problem with my schematic is the fan will be off until the RC turns on the base so I've actually created the opposite of what I need. I also am guessing VR1 would be better at the base of the transister?
**broken link removed**
I am a noob and this is my first post. Your help would be hugely appreciated. Many thanks.
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