Mixed circuit "Timer"

Mixed circuit project "Timer"
Timer based on capacitors charging time, with a transistor logic.

Scheme



 * C1, C2 - "charging elements", more capacitors will increase the time.
 * Q1 with role a logical "not", when capacitors charged, then voltage equal to 0, but with this transistor - voltage exist.
 * R2 placed for tests, in the experiment it is LED, visualizing the process.

Plot



 * [0, 4] seconds: slowly growing, this time possible to increase by adding more capacitors
 * [4, end] seconds: regular grow of capacitor, but inverted by "not" transistor
 * 1) [11, end] seconds: enough voltage for LED, in this period of time the LED must emmit

Experiment
Tested on a breadboard. ~14,15 second is starting to emit, -1,2 sec for connection.



How to make better
LED is starting slowly, like a curve, but for time important the straight point.

Read more:

Schmitt trigger