Hi everyone, I'm new to this forum. I'm working on a senior project where we are using ultrasonic transducers at very high frequencies. Problem is we only have some weaker 25V power supplies to drive the transducers. To fix this problem we were going to purchase a power amplifier but due to the expense, we started looking for alternatives. We found an article titled "Power Amplifier for Ultrasonic Transducer Excitation" which I have scanned and attached as a PDF below. It's a 7 page document. http://www.bambuilt.com/images/Power%20Amplifier%20for%20ultrasonic%20transducer%20excitation.pdf [Broken] The article describes how to build a power amplifier using 2 Mosfets, a driving circuit, and a transformer. I'm not very experienced with electrical diagrams and I'm having a hard time understanding the circuit schematics. The only experience I have with circuits outside of building them is an EE for non-majors course. Below you'll find the basic schematic for the power amplifier that I'm trying to reproduce from page 4 in the article. http://www.bambuilt.com/images/Basic%20Schematic.jpg [Broken] I understand all of the basics, but I do not understand what the Vbias and Vcc do, or what they are for that matter. I also don't really understand the fundamentals of a transformer and how it fits into the schematic. Can anyone explain maybe in simpler terms how this circuit would function and what it would do? Next is the detailed schematic used in the article found on page 5. http://www.bambuilt.com/images/Detailed%20Schematic.jpg [Broken] It is the exact same as the basic schematic, just with all of the details filled in. From what I can tell, they are using two power supplies for the driving circuit set at 3.85V. I'm unsure what the 1.4 means. On from there they run into some basic circuit elements and then on to M1 and M2 mosfets. I still do not understand what the Vbias or Vcc are in this diagram. They look to be DC power sources, one at 3.8v and one at 1000V? I'm very confused on this part. Also as mentioned above, I don't understand how the transformer works in the schematic. Honestly I don't even understand why the entire section off to the right is not connected to the rest of the circuit. Does it have anything to do with the K1 coupling written in the upper right? As you can probably tell, I'm a newb when it comes to this stuff. I'm not entirely concerned with understanding the deep down details of this circuit. I'm just trying to build a small power amplifier to drive our transducers at 500V or so. Thanks in advance for any help you can give. Big or small, anything would probably help in my understanding. I'd love to just be able to place an order from DigiKey or similar and build this thing, but I do understand that I've got a bit of learning to do before I can start ordering components.