# How to get started for building the amplification circuit

1. Mar 5, 2012

### Chuck88

I am planning to build the amplification circuit to amplify the signal from my signal generator by myself. Can someone tell me the what type of materials are necessary for me to get started? What kind of book will be helpful?

2. Mar 5, 2012

### Bobbywhy

If you give more specific details you are more likely to get more useful suggestions. Describe your project and its objectives or purpose.
1. What kind of signal from your signal generator are you trying to amplify?
2. Does the signal generator have an "output level" adjust?
3. What will be your "load"...that is, what are you trying to drive with this amplified signal?
4. How much voltage or power is needed?

There are manufacturer "application notes" for practically any kind of amplifier you may need and tons of information free on the internet. Once you give your plan members here can guide you to books and other sources.

3. Mar 5, 2012

### Chuck88

1. The signal I am going to amplify has the voltage of 10V and frequency of 1.7MHz. I plan to amplify the signal to 100V and 1.7MHz.
2. I am so green that I do not quite know what "output level" is. Can you explain that to me?
3. I am going to apply the amplified voltage to a piezoelectric disk. Based on the materials I read, I think the piezoelectric disk could be treated as a capacitor.
4. The voltage I need is 100V and I think that the power does not mean a lot for my experiment.

4. Mar 5, 2012

### Bobbywhy

Often signal generators have a control that enables you to control the output voltage level. I am only asking if your generator does have such a control.

So your signal generator gives 10V output. How do you know that? Did you measure it with an O'scope? An AC voltmeter? Is it 10V peak-to-peak or 10V rms?

Your amplifier will need a power supply with slightly greater than 100 Volts. By convention, this is considered "High Voltage" so caution for your own safety is MANDANTORY. The capacity of this power supply needs to be enough to drive your load. It takes energy (that means power here) to drive the piezo disc.

I recommend a high voltage FET amplifier for your project. It is fairly cheap, reliable, and simple to build.

Will you apply the 1.7MHz to the piezoelectric disc continuously? If yes, it may overheat.

Last edited: Mar 5, 2012
5. Mar 5, 2012

6. Mar 5, 2012

### Chuck88

I measure the output signal with the multimeter. 10V is the peak-to-peak voltage. I will apply 1.7MHz to the piezoelectric disc continously. If it is overheated, I will buy a new one. Thanks for your remind.

7. Mar 5, 2012

### Mike_In_Plano

Hmmm, 1.7MHz at 100V into what's probably a heavily capacitive load. This does sound difficult for your typical linear amplifier.

Ultrasonic baths typically use power oscillators for this. My personal favorite is the Royer oscillator, and I've taken it up to this level using mosfets. If you wish to do so, I can give you some suggestions, offline, but you'll need to make yourself a transformer and likely an inductor. Otherwise, it's fairly simple and can be built on perf board and powered from 12 volts.

You'd also need access to an oscilloscope to ensure it's doing what you want.

8. Mar 5, 2012

### Chuck88

Thanks for your reply. But if I am going to use the royer oscillator, I have to buy a DC voltage supply. I do not have the DC voltage supply which could provide 12 VDC. And also to build the transformer is not very easy for me to do. Can I use some type of amplifier which could be got on market?

9. Mar 6, 2012

### sophiecentaur

It worries me that you profess to know so little about electronics yet you envisage getting down and dirty with 100V of RF. At the very least, you could end up with some nasty RF burns. What are you planning to use this 100V signal for and what would be the resistance of the load? 50Ohms is a common value at RF and that would correspond to 500Watts of power. That's a mighty meaty bit of kit my friend.