How to generate 250v?

[ydewit]

I am a bit confused and I am sure it's my fault.

This little piezo pump needs 250v and frequencies of 100-300Hz to pump liquids/gas. I had the impression that this would be a low power device, but if so how could I generate 250v using a battery?

**broken link removed**

 

[colin55]

The more energy you deliver to the pump, the more liquid will be delivered.

 

[ydewit]

Yes, but 250V? Even the power outlet of my house is just 110/120v. How am I supposed to generate 250V? (sorry but I am a little new to this)

 

[cobra1]

dont suppose you have a link to the pump??

 

[ydewit]

dont suppose you have a link to the pump??

The link is in my first post. It's basically a whole site to talk about the pump. Here is the technical data:

**broken link removed**

And how to drive the pump:

**broken link removed**

 

[Ubergeek63]

that is easy - capacitive voltage doubler

 

[Ubergeek63]

Yes, but 250V? Even the power outlet of my house is just 110/120v. How am I supposed to generate 250V? (sorry but I am a little new to this)

hmmm... get a crappy little dual primary transformer, wire the primaries in series, connect 110 to half the resultant winding and the piezoelectric across the whole thing

 

[colin55]

hmmm... get a crappy little dual primary transformer, wire the primaries in series, connect 110 to half the resultant winding and the piezoelectric across the whole thing

You are going to need something like a 555 and a small transformer

 

[Diver300]

Why not buy their dedicated controller?

**broken link removed**

That gives you the control of the voltage and frequency that you need, and is its maximum current is probably so small that it can't give you a bad electric shock.

 

[Jaguarjoe]

This pump only requires less than 1/4 watts, its more like 1/8 watt. When I was a kid I made high voltage like this using a "backwards" filament transformer and a pair of 2N255 power transistors.
A function generator IC like the old 8038 or 2026(Ithink), A power op-amp, a pair HV transistors, and a fixed 250dc supply would make an interesying driver.

This might be of value too:

Tiny Inverter Transformer-The Electronic Goldmine

Its not quite 230 volts but I'd bet you can squeeze that little bit more out of it, or buy two (they're cheap) and connect the secondaries in series, now you'll need a pot to trim it down.

 

[ydewit]

Humm, I saw a video where they had a bulky OEM/prototyping driver and assumed this one was the same... I guess not: this is actually great (until I see how much it costs)!

Why not buy their dedicated controller?

**broken link removed**

That gives you the control of the voltage and frequency that you need, and is its maximum current is probably so small that it can't give you a bad electric shock.

 

[ydewit]

I guess at first the concept of turning 2.5V-5VDC into 100-230V seemed like generating more output than the input: something that is impossible. So how can an inverter generate more voltage from a smaller input voltage? Would it be correct to visualize this as a circuit that buffers enough voltage up to 230 and then deliver it at a fraction of the original current so the overall power the the same?

This pump only requires less than 1/4 watts, its more like 1/8 watt. When I was a kid I made high voltage like this using a "backwards" filament transformer and a pair of 2N255 power transistors.
A function generator IC like the old 8038 or 2026(Ithink), A power op-amp, a pair HV transistors, and a fixed 250dc supply would make an interesying driver.

This might be of value too:

Tiny Inverter Transformer-The Electronic Goldmine

Its not quite 230 volts but I'd bet you can squeeze that little bit more out of it, or buy two (they're cheap) and connect the secondaries in series, now you'll need a pot to trim it down.

 

[Diver300]

I guess at first the concept of turning 2.5V-5VDC into 100-230V seemed like generating more output than the input: something that is impossible. So how can an inverter generate more voltage from a smaller input voltage? Would it be correct to visualize this as a circuit that buffers enough voltage up to 230 and then deliver it at a fraction of the original current so the overall power the the same?

There are lots and lots of ways of bumping up voltage. As you say, the current will always be less, so that the power will always be less, maybe only slightly less, after the conversion. It isn't unusual to increase voltage. Camera flashguns do it, as do car ignition systems. The power grid is generated at moderate voltages, maybe 30,000 V, and sent down power lines at 250,000 V to 500,000 V.

There are also lots of ways of looking at voltage increasing devices. Look at force increasing devices, like car jacks. I can't lift my car, but with a jack I can. The handle of the jack travels much further around and around than the car rises.

Some converters use inductors. They work a bit like a hammer. To drive a nail, a large force is needed, more than you can get by shoving. So you accelerate the hammer over a distance, maybe 6 inches or so, and the hammer stops in a much shorter distance, maybe thousandths of an inch, and it takes a lot more force to stop the hammer in such a short distance.

You can't change the current in an inductor instantly. A low voltage increases the current in the inductor, slowly, over a long period of time. Then a switch opens and the current is stopped very quickly. The big voltage that stops the current quickly is generated by this, like the big force from the hammer.

What can make it difficult to understand, is that in many applications, the "long period of time" that I referred to is a few microseconds.

 

[crutschow]

I guess at first the concept of turning 2.5V-5VDC into 100-230V seemed like generating more output than the input: something that is impossible. So how can an inverter generate more voltage from a smaller input voltage? Would it be correct to visualize this as a circuit that buffers enough voltage up to 230 and then deliver it at a fraction of the original current so the overall power the the same?

You are correct. You can't increase the power. But power is volts times amps so if you increase the voltage the available current is less for a given power. That's the purpose of a transformer. It performs that conversion.

 

[ydewit]

I think this makes sense now. I read 230V and was ready to run away... little I knew it was from my own ignorance.

And I guess for this specific pump, since it is driven by a piezo, the greater the peak-to-peak amplitude the greater the piezo will move, which in turn means a greater flow rate.

thanks for the all the replies.