Elmo 16-CL - Page 44

4. Delay Circuit :
^S5
VCC=37V
The nature of Zener Diode is put to use in Delay Circuit.
Zener Diode: * Current flows in forward direction.
* Current does not flow in reverse direction when
applied voltage is lower than a certain level
which is called "Zener Voltage (VD)".
* Current starts to flow in reverse direction when
applied voltage exceeds the Zener Voltage (VD).