L Meter Click Board™

The L-Meter Click Board™ contains all the necessary components needed for a reliable measuring of coil inductance L, which in combination with host MCU makes it ideal in all applications where accurate inductance measuring is needed.Featuring four standard different SMD footprint size and two universal connectors for trought hole components, it's universal tool for any development.

How Does The L-Meter Click Board™ Work?

The principle how L meter Click Board™ works is very simple. In series with the measured coil is C1 capacitor, thus forming the LC circuit when the coil is present. The reference value on a high-speed voltage comparator LM311 is a half of the power supply voltage 2.5V. When the coil is added to the comparator input, the transistor briefly drops the coil to the ground, which is at on the half of the power voltage. The coil and the capacitor then start oscillating a resonant frequency that depends on the capacitor and the value of the coils. Since the capacitor has the fixed capacitance, the only variable is the inductance of the coil which can be calculated by:
2 * pi * F = 1 / sqrt (L * C)

This Click Board™ is designed to use only next mikroBUS pins: PWM output as a Trigger signal and INT – Hardware Interrupt that receive a square wave frequency output from Click Board™. Pins PWM and INT and are labelled as TS and FO, respectively. The board has two type of terminals for a coil connection: TB1 screws terminals and TS2 female header terminals. L meter Click Board™ also have four blank SMD places, to allow soldering different SMD coils for measuring directly onboard .

SPECIFICATIONS

PINOUT DIAGRAM

This table shows how the pinout on L meter Click Board™ corresponds to the pinout on the mikroBUS socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	TS	Trigger switch
	NC	2	RST	INT	15	FO	Frequency out
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
	NC	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

ONBOARD SETTINGS AND INDICATORS