I'm working on a simple project with 555 timer. I'm trying to generate a high-state output for 10s when Vcc is applied to the circuit(It is initially off). However, I have not managed to operate the timer correctly due to self-triggering problems.
It was my first attempt to self-trigger problem according to some examples I found on the internet. Trigger is oscillating between 4V-8V in this configuration which leads to repeated negative-edge transition on the trigger pin; therefore, output never falls off zero volt. Secondly, I've tried a zener in parallel with 470uF capacitor to regulate voltage at trigger pin to prevent another hi-lo transition; but, it has failed again. After 3-4 hours of research, I haven't found a solution yet. In short, the problem is to generate a self-trigger mechanism to 555 timer without any external interventions except turning on/off Vcc. Any idea or explanation will be very helpful.
edit: As Dave suggested, I connected an RC network for triggering purpose and got output as I desire. Following graph is the transient response of that configuration.
Blue: Out Green: Trigger Red: Threshold
I didn't get a point here. As I know, 555 timer set its output high in monostable mode when trigger has a hi-lo transition. What am I missing?