using PC as measure device

It`s fast and easy - using notebook
for measure in electronic.

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Last Update:

Jan 5, 2009

USB Amper
USB Fr. count
USB Voltmeter

LCmeter wiht range C: 0,1pF - 1 uF , H : 0 - 1 mH, USB connection and good accuracy.

General
Description

This LC meter is a small module with good electrical properties. It allows the measurement of very small capacitors and inductors (pF, nH).
It is designed for quick and easy measurement of capacitors and inductors. LC meter is connected with the PC via USB cable and is also powered via this cable. L or C values are displayed on the monitor of a PC or notebook.
LC meter is designed with regard to achieve good electrical parameters with the minimum requirements for hardware. Switching measurement L and C are performed with one button on the module. Software in the PC will automatically detect whether measured L or C. This LC meter is especially suited to measure very small capacitors and coils. LC meter also does not need an power supply - needed current takes from PC (via USB).).

Properties

    * Measuring range : C : 1pF - 2 mF, H : 1 nH - 1 mH
    * Resolution : C : 0,1 pF , L : 0,1 nH
    * The dimensions of module : 40 x 45 mm
The modules are electrically connected directly with the PC.

Block
diagram of LC meter

1.LC oscilator.
Base of LC meter is oscillator, consisting of LM311. Its frequency is about 500 kHz. The measurement of capacity and the induction is based on changes in the frequency of the oscillator. Signal from the LM311 is amplified by transistors BF847 and forms to the level of TTL. Signal then continues to the PIC 16F886 microprocessor, where it is further processed.
2. Mikroprocesor PIC16F886
Microprocesor PIC16F886 works in this module as frequency counter. shifting od frequency oscillator is used for the calculation of values capacitors and inductors.

3. USB interface and PC communication.
Connection with PC is implemented by using USB converter with FT 232RL. FT 232RL is a reliable converter from Usart to the USB protocol. It uses its own APIs and offers a lot of capacity for communication PC with a USB device.