Hi all,
I build a reset circuit similar to the attached schematic which i found in the internet.
The only thing i changed is resistor to 100k and the 0.1uf cap to 47uf to have a delay of around 5 secs. The output 3 is triggering a BC557 transistor instead of the 74ls05. The goal is to set a reset line once to 0v after 5secs for a short time and release it after.
It seems to work for triggering the transistor and setting the line to 0.6v after 5secs, but the output stays high. How can i change the circuit to set the output 3 of the ne555 back to 0 after 0.5secs?
Thanks
I build a reset circuit similar to the attached schematic which i found in the internet.
The only thing i changed is resistor to 100k and the 0.1uf cap to 47uf to have a delay of around 5 secs. The output 3 is triggering a BC557 transistor instead of the 74ls05. The goal is to set a reset line once to 0v after 5secs for a short time and release it after.
It seems to work for triggering the transistor and setting the line to 0.6v after 5secs, but the output stays high. How can i change the circuit to set the output 3 of the ne555 back to 0 after 0.5secs?
Thanks
Attachments
Last edited:
if you need the reset to act with a tempo you need two 555 in series.one will make the tempo, the other,the reset impulse.
Be careful with big caps on reset pins.
When the system is turned off the power supply discharges but the reset cap doesnt and can latch up the chip.
Put a diode cathode to cap+ and anode to power supply rail.
When the system is turned off the power supply discharges but the reset cap doesnt and can latch up the chip.
Put a diode cathode to cap+ and anode to power supply rail.