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9 Feb 2012

dangerousprototypes.com writes:

We’ve been researching various component testers, and BrentBXR tipped us about this high-resolution capacitor meter. It’s accuracy is claimed to be around 0.2%, which is much lower than typical capacitor tolerances.

Internal comparators in a PIC16F628 create an oscillator with the capacitor under test. The oscillator frequency is proportional to the value of the capacitor. An internal timer measures the period of oscillation and calculates the capacitance. Most high-accuracy capacitor meters seem to use this technique, it’s something we’ll look at closely in the coming weeks.

High resolution capacitor meter - [Link]

9 Feb 2012

This is a simple inductor and capacitor measurement tool. The part to test is connected to an oscillator circuit, and the frequency of oscillation corresponds to the value of the capacitor – [via]

All I do is use the LM311 square wave output as pulses to a 16bit counter, and another 100mS periodic timer to count how many pulses per 100mS interval, to calculate the oscillation frequency. BTW, the PIC32 is running off a 16MHz crystal. I average the results from 5 consecutive readings, so I have a 0.5second measurement repeat rate. Good enough. It seems to be accurate enough for my needs, which is basically identifying components that I salvage, or coils that I wind myself.

LM311 oscillator based LC meter - [Link]

9 Feb 2012

freecircuits.org writes:

AS with many tinkerers and junk electronics collectors, a variety of “acquired” power supplies wind up on the author’s shelves to await attention. But are they worth keeping? Testing them with a resistive load is messy and difficult, and with high current supplies it is nearly impossible, unless you have a carbon pile! The tester whose circuit diagram is shown in Fig controls supply currents to 20A, and voltages from 1·7V to over 50V. Current control is so stable that once the current is set, a supply voltage can be varied across this range and the current will remain constant. Maximum power will depend upon how well the pass transistors utilize heatsinks.

Power Supply Tester circuit - [Link]

9 Feb 2012

freecircuits.org writes:

This simple LED tester consists of a current source with a potentiometer that can be used to adjust the current. The current source is implemented using a type TL081 opamp. The output current of the opamp flows through the diode and R2. The voltage drop across R2 is fed back to the inverting input and compared with the reference voltage, which is set with R1 and applied to the non-inverting input. The adjust- ment range is approximately 0–30 mA, which is suitable for testing all normal LEDs. If you wish, you can connect a multi- meter across the LED to measure the voltage on the LED. For the power source, a good option is to use a small laboratory power supply with the output voltage set to 5 V. It is convenient to fit the potentiometer with a scale so you can see directly how much current is flowing through the LED. In order to calibrate the scale, you can temporarily connect an ammeter in place of the LED.

Simple LED tester circuit - [Link]


8 Feb 2012

circuitvalley.com writes:

This is a simple application of internal 10-bit ADC (analog to digital converter) of PIC16F676 microcontroller.you can use this circuit to measure up to 30 v dc. the possible applications are on bench top power supply or as a panel meter in various system.

MICROCHIP’S PIC16F676 is the heart and brain of this circuit .the internal adc of the mcu with a resistor network voltage divider is used to measure the input voltage . then 3 digest of comm anode 7 segment display is used to display final converted voltage. as you can see in the schematic the displays are multiplexed with each other . means we switch on one display and put the corresponding digit on this while other two displays are off this cycle go for each of the display.

Panel Voltmeter Using PIC16F676 - [Link]

7 Feb 2012

circuitvalley.com writes:

This is a simple application of internal 10-bit ADC (analog to digital converter) of MSP430G2231 microcontroller.you can use this circuit to measure up to 30 Vdc. the possible applications are on bench top power supply or as a panel meter in various system.

TEXAS INSTRUMENTS MSP430G2231 is the heart and brain of this circuit .the internal adc of the mcu with a resistor network voltage divider is used to measure the input voltage . then 3 digest of comm anode 7 segment display is used to display final converted voltage. as you can see in the schematic the displays are multiplexed with each other . means we switch on one display and put the corresponding digit on this while other two displays are off this cycle go for each of the display.

MSP430 based 30V voltmeter - [Link]

7 Feb 2012

www.simpleavr.com writes:

This is a simple rf spectrum analyzer project based on TI Launchpad. i have been working on other rf transceiver projects and in need of a simple rf spectrum analyzer to help me visualize what’s happening.

This is a linux project, i had given attention with my best knowledge to make provisions so that it can be built under windows. however i do not have the time and resources to try out everything under windows.

I did successfully built and run the project under windows 7 w/ TI CCS IDE, for host visualization script, it also works under windows but required you to install some unixish packages (cygwin and more)

I need something simple to show the pattern of frequency hopping. i do not need very accurate display of rf power. the Launchpad came in handy as it is inexpensive and contains fast ADC functions. the included usb to uart is a plus as i can communicate data between the MCU application w/ a PC side application for visualization. there are around a dozen or so commands that you can issue via SPI to control the RFM12B, as well as sending and receiving data.

RFM12B Spectrum Analyzer - [Link]

5 Feb 2012

dangerousprototypes.com writes:

Arhi made use of his precision LCR meter to measure capacitance and ESR values of ceramic, tantalum, and electrolytic capacitors. He made his measurements at various frequencies to help him graph the changes to the values over a wide frequency range.

From the graph it can be extrapolated that the ceramic capacitors have the lowest ESR values at any frequency up to the measured 100KHz. While the tantalum capacitors seem to be the most stable of the group.

Ceramic, tantalum, and electrolytic capacitor comparison - [Link]

4 Feb 2012

coremelt.net writes:

With this tool you can test various electronic components like diodes, LEDs, all kinds of transistors (PNP, NPN, several types of MOSFETs), capacitors, resistors as well as triacs and thyristors. It will show you several physical characteristics after the test was completed, like forward voltages, (gate) capacity and amplification factor. More over, it will show the polarity of the component and identifies the several pins of a package. A very nice and sophisticated project I host for Markus Frejek. I’ve done an additional layout for the device you can see on the left side. This project has found a lot of fans, including myself. The device is powered by an AVR ATmega 8 MCU.

Component tester - [Link]

3 Feb 2012

Here is an interesting electronics gadget. It’s a semiconductor component tester that displays the type, pinout, and some relevant specifications of the device connected to its probes. [via]

It doesn’t matter how you connect the test clips to the component, the Atlas DCA can analyse a vast number of different component types including bipolar transistors, enhancement mode MOSFETs, depletion mode MOSFETs, Junction FETs (only gate pin identified), low power thyristors and triacs (less than 5mA trigger and hold), diodes, multiple diode networks, LEDs, bi-colour and tri-colour LEDs. It will even identify special component features such as diode protection and shunt resistors in transistors.

Semiconductor analyser determines part type and value - [Link]



 
 
 

 

 

 

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