Electronics & Software – Tips & Guide


What is the difference in zener diode and resistor

What is the difference in zener diode and resistor?

a Zener diode allows the current to flow when a certain voltage is reached. a resistor limits the current all the time, whatever the voltage.

A live-polarized Zener diode has almost no resistance, a reverse-biased diode appears as an open circuit. resistance to constant resistance regardless of the voltage source

the impedance of a resistor remains constant with the voltage variations, whereas a Zener diode has a high impedance but decreases very gradually with the increase until the Zener voltage is reached. the impedance drops drastically with increasing voltage.

a resistor is simply a calibrated conductor that allows a defined amount of current to flow at a defined voltage. the current can flow equally in both directions. a zener diode will allow the current to flow in one direction with only a small amount of resistance to produce a forward voltage. in the opposite direction, little or no current will flow until the voltage is high within a specific voltage. once the voltage threshold is crossed, the zener diode allows a large amount of current to flow.

in simple terms, a resistor is usually made of a material that does not break down electrically and that retains the same resistance value. In a zener diode, the inverse resistance is first very high, but when a certain reverse voltage is reached, this high or insulating resistance collapses under the effect of an electric current and passes the current. the system is reversible provided that the rated Zener current is not exceeded. In 1950, I noticed a failure of the base-emitter junction of the transistor when we built multivibrators and a supply voltage of about 14 volts was reached, the frequency of multivibrators no longer varied. I used a germanium transistor, but the silicon transistors fail at the base with a reverse voltage of about 8 volts. I should have published it myself.

See the beautiful illustrations of Loring. I just added a warning.

Although both are passive to two ports (no gain), one is primarily linear (resistance), the other is intrinsically non-linear with respect to its current vs. voltage characteristic.

However, each real resistance becomes nonlinear once its nominal values ​​are exceeded and behaves like a fuse. each diode (and the Zener diode is no exception) acts as a resistor for small signals if it is polarized correctly (see weak signal or differential resistance).

some resistors, such as integrated diffusion resistors, are not linear even under normal circumstances.

In real life, everything is linear if the changes are small enough and everything is nonlinear if the changes are large enough.