build a FET voltmeter (KP303E,BF245,2N3823)

thingiverse

It seems like this text is a guide or tutorial on how to build an electronic circuit, specifically a meter or a measuring device. Here's a breakdown of the content: **Introduction** * The author mentions a universal switching diode (SAY17) and suggests a replacement with another diode (1N4148). * The author warns about leakage current in reverse mode. **PCB Design** * The PCB size is 80x50mm. * Material: fiber glass epoxy, FR4 recommended. * Instructions for construction details and initial adjustments will be provided later. **Chassis/Case** * The input impedance of the circuit is high. * Consider using a metal chassis similar to those used in tube amplifier builds. * See pictures of the completed build on the author's website. **Hints** * Take transistors from the same production lot. * If possible, select transistors by gain and current. * Thermal coupling of transistor pairs can improve stability. **Build Experience** * The author shares a personal experience building an unshielded version of the circuit. * The meter was extremely sensitive to changes in the near field. **Representation of Design Artwork** * The author suggests two methods for creating a representation of the design artwork: 1. Using pixel graphics software (e.g., Gimp) and loading pictures into Tinkercad. 2. Using PCB CAD software, scanning or digitizing old pictures, and processing them with Gimp. **Additional Resources** * The full article can be provided for individual non-commercial use only. * A 3D animated visualization of the design can be viewed on Tinkercad.com. If you're interested in building this circuit, I'd be happy to help you understand the instructions and provide additional information or clarification where needed.