Designing a 555-Based Monostable for 3.3s Pulse

[TsAmE]

Homework Statement

Design a 555-based monostable which outputs a constant pulse 3.3s long each time a button is pressed (whether the button is pressed briefly or held down). Use a 1µF timing capacitor. Indicate all component values. What voltage should be applied to pin 5 to double the output pulse duration?

Homework Equations

None.

The Attempt at a Solution

How does the 0.1µF capacitor help output a single pulse (whether the button is pressed briefly/held down)? In my notes it said that if RC (of 0.1µF capacitor and 10k resistor) < RC of monostable (1%), the timing period will stay the same whether the input remains low or goes low briefly. I don't really understand this.

 

[Valkarie]

The output pulse should be 3.3s long. The formula for calculating the timing period is: T = 1.1*RC. Therefore, RC = T/1.1 = 3.3/1.1 = 3s. Since the timing capacitor is 1µF, the resistor should be 3MΩ. The voltage applied to pin 5 should be 2V in order to double the output pulse duration.