Metering – Instrument Projects

A Microcontroller Based Digital Lock-In Milliohmmeter using ATtiny2313 microcontroller

A milliohmmeter is just the tool for checking trace resistance on a printed circuit board, tracking down shorted traces, and measuring the contact resistance of a switch or connector. Its the kind of tool that would come in real handy occasionally, but not often enough to justify shelling out hundreds of dollars. Wanting one anyway, […]

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TRUE RMS-TO-DC Adapter For DVM using microcontroller

Specifications Input: AC, DC or AC+ DC to > 10 KHz Ranges: 200 mv, 2V, 20V, 200V, 600V full scale Accuracy: ±1%, depending on divider resistor selection Crest Factor: 1 to 3, up to 5 with degraded accuracy Input impedance: 1 Megohm shunted by 20 pf Battery drain < 300 uA Introduction The DVMs in

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A Pretty Good Wattmeter For Bench Use using microcontroller

A Pretty Good Wattmeter For Bench Use using microcontroller

Briefly, • AC True Watts using two quadrant multiplier • Optimized for 120 VAC (can be changed) • 15 watt full scale (can be changed) • Uses DVM floating on AC Neutral as display • Requires moderately high level of analog circuit skill • Very inexpensive Find updates at:  www.projects.cappels.org Introduction I am doing some

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RS-232 Freq. Meter/Pulse Generator Based on Atmel ATtiny2313 using microcontroller

Simplicity in circuitry was the design direction. Zero mass (firmware only with no physical components) would the ultimate achievement. This instrument doesn’t have any front panel controls because the user interacts via an RS-232 terminal program at 9600 baud. I needed a frequency meter for my experiments in Nondu, Thailand, where I really don’t have

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Preamp and 330 MHz Prescaler for A Little More Serious Frequency Meter using microcontroller

Preamp and 330 + MHz Prescaler for A Little More Serious Frequency Meter using microcontroller

Overview After finishing Little More Serious Frequency Meter I had planned to make a suitable preamp and prescaler for it, and set about to gather ideas and parts. I was inspired by one fellow who had built the meter and the 2 line X16 character LCD display to show the output, succeeded in designing a

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A Little More Serious Frequency Meter using ATtiny2313 microcontroller

This is design for a frequency meter based on AVR microcontrollers. Maximum input frequency is specified to be 30 MHz in the multi-chip configuration, and in single-chip configuration, there are both 5 MHz and 10 Mhz versions operating with 10 and 20 MHz crystals, respectively. All versions have 9 1/2 digit resolution. I have  used

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LC Determination by Resonant Frequency Measurement using microcontroller

A well known L/C measurement circuit is pressed into service to make a bare bones measurement circuit. Download the AVRStudio assembly source: lgm031227I.asm. Download the AVRStudio hex file: lgm031227.hex. Left-to-right: The 5 volt regulator, the LM393 oscillator (a 0.047 uf capacitor is mounted on the LC circuit connector), the AT90S2313, and the serial connector to

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A 10 Bit LED Digital Panel Meter With Auto Ranging Based On The ATMEGA8

Downloads Download the AVRStudio assembly source for the program: M8DPM091109A.asm Download the AVRStudio hex file: M8DPM091109A.hex Find updates at www.projects.cappels.org Overview – A 10 bit digital panel meter for positive voltage only. – Input resistance: about 130k – Ranges: 0 to 10.20 volts and 0 to 102.3 volts. – Over range indication. This project came

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