Hello,
just for learning I would like to use a 555 in astable mode to blink 2 LEDs with 2 BJTs
The exit of the 555 is wired to:
the base of BTJ BC548C NPN
the base of BTJ PN2907A PNP
Just for exercise I would like to have an astable 555 with 2 BJTs (a NPN and a PNP) and 2 leds.
The output of the 555 is about 3.92V : when HIGH the NPN must be saturated and turn on the red led,
when LOW the PNP must be saturated and turn on the green led.
Vcc 5V is external.
What I don't understand is why I get such current on the green led when it should be off.
On the simulator I see about 1mA but, in reality, I get 4mA (and I think it is too much).
Thank you!
just for learning I would like to use a 555 in astable mode to blink 2 LEDs with 2 BJTs
The exit of the 555 is wired to:
the base of BTJ BC548C NPN
the base of BTJ PN2907A PNP
Just for exercise I would like to have an astable 555 with 2 BJTs (a NPN and a PNP) and 2 leds.
The output of the 555 is about 3.92V : when HIGH the NPN must be saturated and turn on the red led,
when LOW the PNP must be saturated and turn on the green led.
Vcc 5V is external.
What I don't understand is why I get such current on the green led when it should be off.
On the simulator I see about 1mA but, in reality, I get 4mA (and I think it is too much).
Thank you!