Forums

zener diode operating current

Started by panfilero February 28, 2012
I want to use this 100V zener, and I'm trying to figure out how much
current it draws when it's turned on, on the datasheet I see

Vz "working voltage" is between 95V-105V with the condition Iz = 1 mA

does that mean that as long as I make sure the zener is capable of
getting at least 1mA that this will conduct when I go over 100V?

here's the zener I'm looking at

http://www.nxp.com/documents/data_sheet/BZX100A.pdf

thanks!
panfilero wrote:
> I want to use this 100V zener, and I'm trying to figure out how much > current it draws when it's turned on, on the datasheet I see > > Vz "working voltage" is between 95V-105V with the condition Iz = 1 mA > > does that mean that as long as I make sure the zener is capable of > getting at least 1mA that this will conduct when I go over 100V? > > here's the zener I'm looking at > > http://www.nxp.com/documents/data_sheet/BZX100A.pdf > > thanks!
Yes. It will likely conduct when Vz is exceeded even if current is limited to something less than 1 mA, but the Iz (1 mA) spec on the datasheet is the level they use to test it. And it will conduct in the forward direction at less than 1 volt. Ed
On Tue, 28 Feb 2012 16:22:54 -0800, panfilero wrote:

> I want to use this 100V zener, and I'm trying to figure out how much > current it draws when it's turned on, on the datasheet I see > > Vz "working voltage" is between 95V-105V with the condition Iz = 1 mA > > does that mean that as long as I make sure the zener is capable of > getting at least 1mA that this will conduct when I go over 100V? > > here's the zener I'm looking at > > http://www.nxp.com/documents/data_sheet/BZX100A.pdf
No (don't you love it when all the responses agree?). It means that if you put 1mA through it, it'll drop between 95 and 105 volts, depending on which one you pulled out of the bin. Look at Figure 5 in the data sheet for an idea of what happens at different voltages and/or currents: as the current goes down the voltage does, too -- it just does so steeply. Keep in mind that the whole plot shifts left or right depending on the diode -- but keep in mind, too that the diode doesn't go from no conduction at all to full conduction over the span of a microvolt. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com
On Feb 28, 10:43=A0pm, Tim Wescott <t...@seemywebsite.please> wrote:
> On Tue, 28 Feb 2012 16:22:54 -0800, panfilero wrote: > > I want to use this 100V zener, and I'm trying to figure out how much > > current it draws when it's turned on, on the datasheet I see > > > Vz "working voltage" is between 95V-105V with the condition Iz =3D 1 mA > > > does that mean that as long as I make sure the zener is capable of > > getting at least 1mA that this will conduct when I go over 100V? > > > here's the zener I'm looking at > > >http://www.nxp.com/documents/data_sheet/BZX100A.pdf > > No (don't you love it when all the responses agree?). > > It means that if you put 1mA through it, it'll drop between 95 and 105 > volts, depending on which one you pulled out of the bin. > > Look at Figure 5 in the data sheet for an idea of what happens at > different voltages and/or currents: as the current goes down the voltage > does, too -- it just does so steeply. > > Keep in mind that the whole plot shifts left or right depending on the > diode -- but keep in mind, too that the diode doesn't go from no > conduction at all to full conduction over the span of a microvolt. > > -- > Tim Wescott > Control system and signal processing consultingwww.wescottdesign.com
got it, thanks!