H
hdjim69
- Jan 1, 1970
- 0
Hi, I'm self teaching myself electronics as a hobby so I don't have
an instructor to ask simple questions of so please forgive me if this
has been explained before.
Regarding using Zerner diodes in reverse bias configuration as a
voltage regulator, I just want to make sure I got this right. Here is
a link to HyperPhysics website displaying a simple voltage regulator
circuit using a Zerner diode:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/zenereg.html
So, let's say the load needs 12v to operate properly and the
Zener's breakdown voltage is 13v. So when the unregulated power
supply's voltage spikes at 13v, are we saying the Zener will fail
"shorted" ? That is, conducting full current flow just like a
piece of wire ? Kinda like a dam failing when too much water pressure
is applied to it ? If so, then when this happens the Zerner is now in
parallel to the load and we know that adding a parallel branch does not
effect voltage or current in the other branches since all branches are
connected directly to the voltage source and the current through that
branch is determined by it's resistance, so the new "closed"
Zener branch has no effect on the load branch. But the key to all this
is the dropping resistor connected in series with both the Zener & load
branch. Now that there's extra current flowing through the Zener
branch, this current will now have to flow through the dropping
resistor too which will now drop more voltage (Vd = I * R thru the
component). So for all practical purposes the circuit is really the
load in series with the dropping resistor. And the Zener just acts
like a control mechanism to the dropping resistor.
Do I have this right ? Is this how Zerner diodes are used in this
configuration ?
J
an instructor to ask simple questions of so please forgive me if this
has been explained before.
Regarding using Zerner diodes in reverse bias configuration as a
voltage regulator, I just want to make sure I got this right. Here is
a link to HyperPhysics website displaying a simple voltage regulator
circuit using a Zerner diode:
http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/zenereg.html
So, let's say the load needs 12v to operate properly and the
Zener's breakdown voltage is 13v. So when the unregulated power
supply's voltage spikes at 13v, are we saying the Zener will fail
"shorted" ? That is, conducting full current flow just like a
piece of wire ? Kinda like a dam failing when too much water pressure
is applied to it ? If so, then when this happens the Zerner is now in
parallel to the load and we know that adding a parallel branch does not
effect voltage or current in the other branches since all branches are
connected directly to the voltage source and the current through that
branch is determined by it's resistance, so the new "closed"
Zener branch has no effect on the load branch. But the key to all this
is the dropping resistor connected in series with both the Zener & load
branch. Now that there's extra current flowing through the Zener
branch, this current will now have to flow through the dropping
resistor too which will now drop more voltage (Vd = I * R thru the
component). So for all practical purposes the circuit is really the
load in series with the dropping resistor. And the Zener just acts
like a control mechanism to the dropping resistor.
Do I have this right ? Is this how Zerner diodes are used in this
configuration ?
J