An Amateur Radio Enthusiast from Brazil. JK De Marco. In these pages Hams will find his ideas on QRP, Antennas and Complete circuits.
PY2WM JK De Marco Projects
A 40 dB RF Attenuator
“To measure power of a high power transmitter, or to be able to observe the output signal on an oscilloscope or spectrum analyzer, it is necessary that the signal is attenuated in accordance with the instrument, while it must be ensured that the transmitter is “seeing” the correct impedance. So it requires an attenuator that works with three ports (input, output, and output attenuated), all while maintaining the correct impedance of 50 ohms.
The circuit assembly and is shown here in EMRFD and also in the QST. When properly calibrated can be used for precision measurements in section 0-500 MHz, or a a calibration capacitor C1, can be used for the range of 0-50 MHz with reliability.”
Other Projects and Ideas
These pages created by Wichit Sirichote of Department of Applied Physics, Faculty of Science, provides schematic and software for hobbyists to practice “learn by doing”, build a simple microcontroller projects at home.
Build Your Own Microcontroller Projects
Some of the projects include – The 4 Channel Pt100 Thermometer, G5-Data Logger, Solar Recorder, 89S52 and PIC Project Board. Even circuits, code and SBC for the popular 8051 can be found here.
I do remember the Intersil ICL7135 very clearly. This year 2011, almost 29 Years, the classic integrating type analog to digital converter is still interested. With a cheap price and easy interfacing, I think I will design a cheap digital volt meter with microcontroller to provide serial interface similar to the Fluke45. Two channels is good for scientific experiment. The serial port RS232 is also nice for interfacing to the PC. Let us see the prototype of the meter in Figure 1. The display for each channel is 8-digit 7-segment LED. It is cheap and very reliable.
Dual Channel Digital Volt Meter
CirKits – Solar Power Electronic Projects
CirKits SCC3 Photovoltaic Charge Controller kit, SPC3 Solar Power Center kit, and DAS1 Dark Activated Switch kit.
SPC3 – 12 Volt 9 Amp / 10 Amp Solar Power Center Kit
The SPC3 kit contains all of the circuitry for a medium-sized solar power system. It includes a solar charge controller for battery charge regulation, a smart on/off power switch with automatic low voltage disconnect operation and a built-in white LED lighting system. Additional lights and other 12V devices can be connected to the load terminals and controlled by the SPC3. The SPC3 can regulate up to 9 amps of incoming solar power and can switch an external load of up to 10 amps.
The kit includes:
- A high quality double sided, silk screened circuit board.
- All of the parts required for building the board.
- A schematic and wiring diagram.
- Easy step-by-step assembly, alignment and usage instructions.
CirKits is a division of SolOrb.