Resistor Voltage Divider Vs. Zener Power Source

Thread Starter

SamR

Joined Mar 19, 2019
5,039
The resistor voltage divider seems to have the price advantage and higher voltage and power Zener diodes are not as common but... From an energy standpoint, the low Zf forward impedance seems to give the Zener the nod from an energy loss standpoint. Am I missing something here?
 

MrChips

Joined Oct 2, 2009
30,790
With resistor voltage divider, the output voltage is not constant. The voltage will drop as more current is supplied to the load.

With a zener regulated circuit, the voltage is relatively constant (depending on the characteristics of the zener) from zero load current up to the maximum designed current. The power consumed is the same regardless of the load current, i.e. power dissipated is the supply voltage x max current.
 

BobTPH

Joined Jun 5, 2013
8,932
If the supply voltage and the load current are both constant, then a voltage divider works and requires only one resistor. We use this to power LEDs often.
 
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