Is this sample question a zener diode - wave shaper question?

[circuit975]

Hello everyone
I am learning Zener diode but something stuck in my mind
Is this zener diode called a wave shaper? So is this information true or false?

 

[Nigel Goodwin]

Not really, it's a crude voltage regulator - however, if you feed it a highish voltage AC signal it will clip the negative side to 0.7V, and the +ve side to 10V - so in that respect it will alter the shape of the signal.

 

[circuit975]

Not really, it's a crude voltage regulator - however, if you feed it a highish voltage AC signal it will clip the negative side to 0.7V, and the +ve side to 10V - so in that respect it will alter the shape of the signal.

hmm thanks actually what I wanted to ask was exactly this: is this diode question example a wave shaping question example?

 

[danadak]

Divining the intention of the author of that circuit discussion is
fortune teller domain. I would lean towards basic V regulator
versus wave shaping, since circuit seems to be fed by DC, or
so my crystal ball seems to reveal.

Regards, Dana.

 

[alec_t]

is this diode question example a wave shaping question example?

Do you see any wave source in that circuit?

 

[aliarifat794]

A Zener diode is not typically referred to as a "wave shaper." It is used for voltage regulation and protection in electronic circuits.

 

[circuit975]

A Zener diode is not typically referred to as a "wave shaper." It is used for voltage regulation and protection in electronic circuits.

this is exactly the answer I was trying to understand thank you very much

Do you see any wave source in that circuit?

does it have to be a wave source to be a wave shaper

 

[Nigel Goodwin]

this is exactly the answer I was trying to understand thank you very much

does it have to be a wave source to be a wave shaper

If there's no wave source then there's nothing to shape - but as we've all said, it's a (crude) voltage regulator.

To be honest, 'wave shaper' is a pretty vague and obscure term that's hardly ever used.

 

[Tony Stewart]

Your intent implies you are searching for this cct with a false assumption. It is not what you assumed.

A wave is bipolar, which requires 2 active polar devices such as diodes to shape a signal unless otherwise defined.

 

[Tony Stewart]

Any non-linear circuit can be called a "wave shaper" but it is a non-value-added description. If that makes you happy, ok.

 

[ZipZapOuch]

The circuit is a voltage regulator - as long as the "load" is 1k ohms or more. As current flow through the 220 ohm resistor is 46mA or more, the zener essentially does nothing because, in that case, the voltage drop across the 220ohm resistor is more than 10v and the available voltage for the load is less than 10v so no regulation is possible.

 

[Ramussons]

On the Positive cycle, the output voltage follows the input voltage and clamps it at 10 volts. It no longer follows the input beyond that..
On the Negative cycle, the same happens except that the clamping is at -0.7 volts.

I presume that Vload >> Rshunt

 

[Tony Stewart]

The circuit is a voltage regulator - as long as the "load" is 1k ohms or more. As current flow through the 220 ohm resistor is 46mA or more, the zener essentially does nothing because, in that case, the voltage drop across the 220ohm resistor is more than 10v and the available voltage for the load is less than 10v so no regulation is possible.

I think differently. A voltage divider with a 220 ohm load would result in 10V without the Zener thus ...220 + 220 = 440.

1. I load = 20V/440= 45 mA maximum with no Zener **
2. Est. 10 V Zener might be rated at 5mA not max current.
3. Rload min = 220 Ohms
4. Pz "maks" = 400 mW thus ...
5. Iz max = 400mW/10V = 40 mA
6. Thus I load min = 45 mA - 40 mA = 5 mA thus ...
7. Rload max = 10V/5mA = 2 k

** (I rounded 0.0454545 to 45 mA rather than 46 mA but that's not an issue.)

Result
Rload = 220 to 2k absolute max or "maks"

 

[ZipZapOuch]

I think differently.

you don't appear to think differently, you appear to think exactly the same but added a refinement for maximum wattage of the zener.

** (I rounded 0.0454545 to 45 mA rather than 46 mA but that's not an issue.)

iyes, you rounded, if would have rounded, my comment about the Zener doing nothing above "46mA" would have been entirely true - because the Zener does do something between 45mA and 45.45mA.

 

[MrAl]

View attachment 146170
Hello everyone
I am learning Zener diode but something stuck in my mind
Is this zener diode called a wave shaper? So is this information true or false?

Hi,

As many others here have said, it's probably a voltage regulator. However, when you ask this kind of question we probably want to stay a little more general. The question then becomes, in keeping with the most general interpretation what do we call a circuit that has a zener diode. If I draw a single zener diode with nothing else, what kind of circuit is that.

The only thing I can think of at the moment is that a zener limits the voltage across it, so the circuit must be limiting something, and that would be voltage, current, or power. That I guess would mean that if we want to stay completely general, we'd have to call it a "limiting circuit". The problem then is we have to ask what it is limiting.
It's funny because when we see an op amp in the circuit we might call it an "op amp circuit". We might not yet attribute any specific function to it, but we usually do. For example, "amplifier circuit", and then we may get even more specific, "voltage amplifier circuit", "current amplifier circuit", "photo diode amplifier circuit", etc.

Ok, so what do we call the zener diode circuit then? Oh wait, I just called it a "zener diode circuit", didn't I. I guess that's the general name then. Now we'd like to get more specific, if possible.

This is where we have to try to interpret the intent of the designer, which is sometimes hard to do. In this circuit we see a 20 volt DC source being applied to a resistor and zener diode, with a resistor across the zener which is the load.
Now we know that zener diodes can be used as voltage regulators, voltage references, and clipping circuits, at the least. So, how does any of that fit with this schematic.

Since we see circuits like this all the time and they are usually referred to as "voltage regulators", I think we can call this a voltage regulator circuit. If we saw a wave generator on the input then I think it would be more appropriate to call it a wave shaping circuit or a clipping circuit. Clipping circuit might have an AC sine wave input and the output is clipped on both peaks to be limited to some required output value. A wave shaping circuit is usually more elaborate, but we could call it that. There's no wave generator on the input though, so that's an indication that it is not a wave shaper circuit or clipping circuit. That does not mean it cannot be used for that, but since the author of the drawing did not show a wave generator, it is much more likely that it is just a voltage regulator or perhaps a voltage reference.
Did the person drawing the diagram make a mistake, maybe it was not the circuit designer that copied the design into a digital form that could be displayed on a computer. If that's the case, then we could argue that no circuit on the web is what it appears to be and so we could never conclude anything about any circuit we see on the web, ever. Although that is a very general outlook, it's not the right stance to take. We believe what we see until we have reason to believe otherwise.

All this means to me that the intent is to show a voltage regulator or voltage reference, and not a wave shaper or clipping circuit. If this is not the original intent, that's too bad, but it would not be our fault for interpreting it wrong because logically that's the most reasonable interpretation.

It does however make sense to question this a little bit because of the rather 'large' 220 Ohm series resistor, but then again some regulator circuits do not have to deal with higher currents. For example, this could be a 9v battery eliminator circuit, and that would most likely not have to put out much current (45ma max with 20v min input) because circuits that run with a regular 9v battery usually do not have to put out much current, and the circuit might be meant to be used with a 15v wall wart (with higher low-current output voltage).

I also want to make it clear that this does not mean it cannot be used for another purpose such as a wave shaper or clipping circuit, but then again you could use this as a paper weight if you really wanted to

 

[Tony Stewart]

you don't appear to think differently, you appear to think exactly the same but added a refinement for maximum wattage of the zener.

iyes, you rounded, if would have rounded, my comment about the Zener doing nothing above "46mA" would have been entirely true - because the Zener does do something between 45mA and 45.45mA.

Sorry to disagree with your statement

"The circuit is a voltage regulator - as long as the "load" is 1k ohms or more.

It creates 10V with RL= 220 or more but overheats with no load or more than 2k.

Cheers,
Tony