‰  NOW 35 WPM  ‰   TEXT IS FROM MAY 2015 QST  PAGE 33‰

USE ONE DROPPING RESISTOR R7 IN COMMON WITH LEDS DS1 DS10.  THE REFERENCE
VOLTAGE FOR THE ADC IS THE REGULATED 5 V POWER SUPPLY OF THE PICAXE.
SWITCH S1 SELECTS EITHER A 9 V INTERNAL BATTERY OR THE EXTERNAL BATTERY
THAT MIGHT BE MONITORED.  WHEN MONITORING AN EXTERNAL BATTERY, THE VOLTAGE
MUST BE ABOVE ABOUT 6 1/2 V TO BE ABOVE THE OPERATING VOLTAGE OF THE 5 V
REGULATOR.  SWITCH S1 DOUBLES AS AN ON OFF SWITCH FOR THE BATTERY AND THE
GREEN LED INDICATES THAT POWER IS ON.  YOU CAN CHANGE THE MONITOR POINT
VALUES BY CHANGING NUMBERS IN THE BASIC PROGRAM.  YOU CAN PROGRAM TIGHTER
RANGES WITH CLOSER STEPS OR DIFFERENT RANGES THAT MIGHT NOT BE LINEAR.
THIS CIRCUIT MAKES AN EXCELLENT CLUB PROJECT.  STEVE ULRICH, NW0C, DESIGNED
A PRINTED CIRCUIT BOARD SO THAT MEMBERS OF THE MINNESOTA AMATEUR RADIO
TECHNICAL SOCIETY MN ARTS COULD BUILD THE MONITOR AT OUR ANNUAL BUILDERS
DAY MEETING.  THE POWER MONITOR THE POWER MONITOR PROGRAM SQUARES THE INPUT
VOLTAGE TO DISPLAY POWER.  IF THE ANALOG INPUT TO THE PICAXE IS A SINE WAVE
ACROSS A 50 LOAD LIKE RL, THE POWER IS THE SQUARE OF THE PEAK VOLTAGE
DIVIDED BY 100.  THE PICAXE CAN DO THAT WITHIN ITS LIMITS OF INTEGER
CALCULATION AND MAXIMUM WORD SIZE.  I USED A 50, 15 W, NON INDUCTIVE
RESISTOR AS AN RF LOAD, A 1N34A DIODE DETECTOR, AND A 0R01 UF CAPACITOR
FIGURE 2 TO CAPTURE THE PEAK VOLTAGE OF AN RF SINE WAVE.  I MEASURE THIS
‰  END OF 35 WPM TEXT  ‰  QST DE W1AW  ƒ