Question

write an conclusion, of the breakdown voltage and resistive component of Zener diodes and loading.

Answer 1

The point at which the zener voltage triggers the current to flow through the diode can be very accurately controlled (to less than 1% tolerance) in the doping stage of the diodes semiconductor construction giving the diode a specific zener breakdown voltage, (Vz) for example, 4.3V or 7.5V. This zener breakdown voltage on the I-V curve is almost a vertical straight line.

Resistor, Rs is connected in series with the zener diode to limit the current flow through the diode with the voltage source, Vs being connected across the combination. The stabilised output voltage Vout is taken from across the zener diode.

The load is connected in parallel with the zener diode, so the voltage across RL is always the same as the zener voltage, (VR=VZ). There is a minimum zener current for which the stabilisation of the voltage is effective and the zener current must stay above this value operating under load within its breakdown region at all times. The upper limit of current is of course dependant upon the power rating of the device. The supply voltage Vs must be greater than VZ.