modified 10 years ago

555 correction

01:51:58

Please help. What I did was wrong but why

published 10 years ago

Karlberg

10 years ago

Hi! First exchange the PNP transistor for a NPN and add a 1k resistor between pin 3 and base of the transistor. Connect the lightbulb between + and collector of transistor. The 555 doesn't lower pin 3 enough to trigger a PNP, a transistor needs a biasing resistor otherwise to much current leak to ground. Hope this helps 😺

Karlberg

10 years ago

Actually all you need is the added resistor but the rest is really good practise 😸

abdo

10 years ago

Thanks alot

Karlberg

10 years ago

No problem 😺

abdo

10 years ago

Hi again, sorry to bother you but i'm a hobbiest. Why the 1.5V isn't affecting the bulb. If i put it to 10v same voltage pass to the bulb

Karlberg

10 years ago

That is why you have to put it between +1.5v and the collector of the transistor. The way it's connected now is between transistor emitter and ground. Hope that helps.

Karlberg

10 years ago

Here's a pic http://ow.ly/i/cV80t

abdo

10 years ago

Yeap thanks alot

Karlberg

10 years ago

No problem 😺

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