Electronics and components

Prenderb

Hi guys, I'm currently planning to build a sound-trigger for the sister's photography. I found some instructions from an american website, but when the sister went into an electronics store this afternoon, some of the components appear to have caused confusion.

What I'm looking for is a 400V SCR, and a piezoelectric element. Am I right in suggesting that these are also the same as a 400V thyristor and a microphone? Is the voltage the only thing that you can specify with a thyristor, or are there other concerns - what I'm asking here I suppose is does one go to the shop and ask for a 400V thyristor or is more info needed? Same for the microphone element/transducer.

2-conductor cable and hookup wire are 2-strand cable and 1-strand wire respectively, I assume? It's being built on a breadboard, hence the hookup wire.

Any help anyone can give would be great! Cheers, Prenderb.

eoinor

Try http://ie.farnell.com/ or http://www.radionics.ie for the components.

Offy

Is a SCR a type of resistor? Im not sure.
Piezoceramics are something Ive designed with and a 400v SCR sounds about right for driving a piezoceramic actuator. Piezos require a high voltage to operate and the drive circuit often cost more than the actuator itself. To drive a piezo the frequency is very important and it wont do anything it the frequency is incorrect. I have detailed circuit diagrams for drive units, if you want copys PM me.

DublinDilbert

Offy wrote: »

Is a SCR a type of resistor? Im not sure.

SCR = Silicon Controlled Rectifier = Thryistor

Which is basically a diode that will only conduct in the forward direction when a voltage pulse is applied to the gate.

Prenderb wrote: »

What I'm looking for is a 400V SCR, and a piezoelectric element. Am I right in suggesting that these are also the same as a 400V thyristor and a microphone? Is the voltage the only thing that you can specify with a thyristor, or are there other concerns - what I'm asking here I suppose is does one go to the shop and ask for a 400V thyristor or is more info needed? Same for the microphone element/transducer.

2-conductor cable and hookup wire are 2-strand cable and 1-strand wire respectively, I assume? It's being built on a breadboard, hence the hookup wire.

Can you post the schematic or a link to it?

Is the SCR/Thyristor being used to switch a high voltage, or just being used for its "latching" capabilities?

If its just been used for latching, you can "build" a thyristor out of a PNP and NPN transistor wired up in a specific way.

Prenderb

Here's the instructions i intend to follow. They are intended to build onto a breadboard, but the circuit diagram is like this.

Dankoozy

digikey charges a lot for shipping, so if you get one thing off them you might as well get the whole lot. they have *everything*. I have their catalogue, 500 pages of absolutely nothing but different types of connectors. I bought a few SMD buzzers off them once but had it sent to england I think because the shipping was more expensive to ireland

Offy

ok I found some of the links that might provide useful information.
http://powerelectronics.com/passive_components_packaging_interconnects/sensors_transducers/power_driving_piezoelectric_actuators/index.html
and
www.apexmicrotech.com.
but for some reason I cant get through to the Apex link?????
I have a lot of pdf's but I've no idea how to post files!

DublinDilbert

Before you add the SCR you can test the circuit with an LED to make sure its reacting to sound, see modified schematic. This will be easier than hooking up to the camera etc...

After you get it working with the LED then add the SCR to the circuit. When choosing the SCR get one with a ratting of a few amps...

Prenderb

Thanks for the LED test tip! We've decided to get the kit from the hiviz website, rather than trying to source the individual components, so once that arrives we'll see how sraightforward it is!