A zener is sort-of like a tank of water with a hole in the side. As long as the hose (resistor) going into the tank is smaller,
the tank will never fill above the hole...

Now, is there a set of components, or a circuit, that achieves what a Shishi Odoshi does?



I know a diac will hold back current until it gets to ~32 volt, and then it dumps the charge until the current goes to zero, then resets.

Does anyone know if diacs are made in a series of voltages, like zener diodes? Or maybe something else?

 

A zener is sort-of like a tank of water with a hole in the side. As long as the hose (resistor) going into the tank is smaller,
the tank will never fill above the hole...

Now, is there a set of components, or a circuit, that achieves what a Shishi Odoshi does?

View attachment 253991

I know a diac will hold back current until it gets to ~32 volt, and then it dumps the charge until the current goes to zero, then resets.

Does anyone know if diacs are made in a series of voltages, like zener diodes? Or maybe something else?

I don't think so and DIACs are pretty much obsolete.

 

Hello,

Have a look at relaxation oscillators that make use of UJT or PUT's.

Bertus

 

Possibly avalanche diodes.

 

I would say it is most similar to a Schmitt-Trigger relaxation oscillator.
A resistor (which limits current) charges a capacitor. As the capacitor charges, the voltage increases until a threshold level which changes the inverter's output from HIGH to LOW and the capacitor discharges through the resistor until the threshold voltage value to get a LOW to HIGH transition and the whole cycle repeats.

Additions can be added like a high value resistor in parallel to the capacitor to represent leakage of the bamboo tube. Change R to a rheostat to show variable flow of incoming water. Anti-parallel diodes in the charge/discharge path with a different value resistor in each diode to separately control rate of charge vs discharge.

 

I don't think so and DIACs are pretty much obsolete.

They still have a few applications, yes? What are they replaced with?

 

I would say it is most similar to a Schmitt-Trigger relaxation oscillator.
A resistor (which limits current) charges a capacitor. As the capacitor charges, the voltage increases until a threshold level which changes the inverter's output from HIGH to LOW and the capacitor discharges through the resistor until the threshold voltage value to get a LOW to HIGH transition and the whole cycle repeats.

View attachment 253995

"Schmitt-Trigger relaxation oscillator" okay! I can do a search on this and figure out how to implement a shiski odoshi in my designs.

 

"Schmitt-Trigger relaxation oscillator" okay! I can do a search on this and figure out how to implement a shiski odoshi in my designs.

I added a second paragraph above for some design control.

 

Hello,

Have a look at the following pages with info on the PUT and UJT:
https://www.eeweb.com/put-relaxation-oscillator/
https://www.allaboutcircuits.com/textbook/semiconductors/chpt-7/unijunction-transistor-ujt/

Bertus

 

Diacs come in varying breakdown voltage ratings but they tend to be in the 39V to 40V range as far as I have seen.
Avalanching collector-base and emitter-base junctions give mor variety.
For high voltages you can also consider the lowly neon lamp.

 

For high voltages you can also consider the lowly neon lamp.

In the pharma world, that's called an off-label prescription!

 

I would say it is most similar to a Schmitt-Trigger relaxation oscillator.
A resistor (which limits current) charges a capacitor. As the capacitor charges, the voltage increases until a threshold level which changes the inverter's output from HIGH to LOW and the capacitor discharges through the resistor until the threshold voltage value to get a LOW to HIGH transition and the whole cycle repeats.

Additions can be added like a high value resistor in parallel to the capacitor to represent leakage of the bamboo tube. Change R to a rheostat to show variable flow of incoming water. Anti-parallel diodes in the charge/discharge path with a different value resistor in each diode to separately control rate of charge vs discharge.
View attachment 253995

Can i ask a question. Is there more circuit in the schmitt inverter not being shown because from my novice understanding there is no reason why this circuit should cycle. If that were just a simple diode why would the capacitor fill any higher than it needs to by pass the diode and then just keep pushing from the excess off the battery. Why dose the capacitor discharge need more than the smallest amount of extra current to continuously pittle out pixies.

However I am such a noob I would say the diode like symbol is facing the wrong way. So, I assume there is more circuit in the schmitt inverter symbol. Maybe, I am missing a whole hell of allot about capacitors.

Or maybe I am using a bad symbol key?

https://www.autodesk.com/products/e...ploads/2017/02/circuit_schematic_symbols1.jpg

 

There is no diode symbol in that Schmitt Trigger relaxation oscillator schematic, that is an inverter with Schmitt Trigger input.

The power connections are not shown.

 

Can i ask a question. Is there more circuit in the schmitt inverter not being shown because from my novice understanding there is no reason why this circuit should cycle. If that were just a simple diode why would the capacitor fill any higher than it needs to by pass the diode and then just keep pushing from the excess off the battery. Why dose the capacitor discharge need more than the smallest amount of extra current to continuously pittle out pixies.

However I am such a noob I would say the diode like symbol is facing the wrong way. So, I assume there is more circuit in the schmitt inverter symbol. Maybe, I am missing a whole hell of allot about capacitors.

Or maybe I am using a bad symbol key?

https://www.autodesk.com/products/e...ploads/2017/02/circuit_schematic_symbols1.jpg

The large triangle in my schematic with one input is generally an amplifier (or buffer). The circle by the output means that it is an inverting amplifier. The fact that there is only one input and one output, it is assumed to be a very high gain digital device (aka a logic chip) that is either on or off. Normally, an inverter logic chip has a single threshold voltage level that triggers the output change. However, The little box with the extra wings inside the triangle means the device has a Schmitt trigger input which means you have to rise up a little beyond the threshold point to get the device to turn OFF (LOW), then the input threshold is a little below the trigger point to turn it ON (HIGH). Note the inverted high-for-low and low-for-high inverter behavior.

In summary, it is not a diode.

 

Is there more circuit in the Schmitt inverter not being shown(?)

Yes. Lots more.

 

The large triangle in my schematic with one input is generally an amplifier (or buffer). The circle by the output means that it is an inverting amplifier. The fact that there is only one input and one output, it is assumed to be a very high gain digital device (aka a logic chip) that is either on or off. Normally, an inverter logic chip has a single threshold voltage level that triggers the output change. However, The little box with the extra wings inside the triangle means the device has a Schmitt trigger input which means you have to rise up a little beyond the threshold point to get the device to turn OFF (LOW), then the input threshold is a little below the trigger point to turn it ON (HIGH). Note the inverted high-for-low and low-for-high inverter behavior.

In summary, it is not a diode.

So when I used the key to read the schematic. I read it in the wrong direction. I should have read it from the outside in, meaning what I was looking at was a inverter with a schmitt trigger in it. Not a schmitt inverter?

(theres a joke here some place about a schmitten inverter that just won't turn off but my vocabulary is not there yet.)

 

Yes. Lots more.

View attachment 254066
View attachment 254068

thank you I will look at this when I have the chance and see if i can pull some understanding out of it.

 

But what if there was a zener that could act like a Shisi Odishi would the physical properties have an exception ?
First lets look at the zener circuit (demo circuit) and the zener's VI charecteristic and thermal properties in turn voltage stability,

What happens if all sorts of diodes charge carrier properties were somehow unrelated to reverse diodes charecteristics
Which diode material would act like a Shishi Odishi ? If another circuit is used to measure what the zener demo circuit does it must be true for every zener typically having zener knee. A special zener that is asked for would have zener's VI charecteristics combined with an accumulative capacitive charge that would release it's charge simalar to a Shishi Odoshi. Like the Edison effect or multipactor effect are harsh to circuits. The laser diode found it's way into cuttng whereas the inductive power conversion is compatable with photovoltaics, the storage is more solid state and the conversion uses electromagnetic type or switching because inductors ability to do work. The voltage reference or zener electrical equivalent has been adapted to voltage reference and frequecy applications in a category not power. Diac does significant work because of the circuit, the zener is constrained by thermal limitations passing the job of heat dissipation to power handling semiconductors. I built a 5W 5V zener supply went back and got a better voltage regulator.

The teacher may have got the question after using the "little green man" analogy for zener diodes
I 'm not sure if the zener symbol has one arm up and one arm down ?