Bulb dimmer circuit

G

Grey

Guest
Suppose I have a TTL IC which has two outputs. I want to drive a small bulb
with a transistor (example NPN BFY51) via a 12V rail.
How hard would it be to drive the bulb so..

If both o/p's = 0, bulb off
output A = 1, bulb on
output B = 1, bulb fades on over 1/2 sec.
output B = 0, bulb fades off over 1/2 sec.

output A+B would not be used.

Graham
 
I drew up a schematic that should work, you can see it at
http://www.fncwired.com/LampDelayEx/

Brian

"Grey" <grahame9@btinternet.com> wrote in message
news:ckc1sv$9d3$1@hercules.btinternet.com...
Suppose I have a TTL IC which has two outputs. I want to drive a small
bulb
with a transistor (example NPN BFY51) via a 12V rail.
How hard would it be to drive the bulb so..

If both o/p's = 0, bulb off
output A = 1, bulb on
output B = 1, bulb fades on over 1/2 sec.
output B = 0, bulb fades off over 1/2 sec.

output A+B would not be used.

Graham
Click to expand...
 
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