inductance meter

I got the idea and schematic from

code is uploading correctly but when i made connections as shown in ckt dia.then arduino does not work.I am not getting what is exact problem

InductanceMeter.pdf (12.6 KB)

You haven't really explained what is wrong.

Hello aarg,

when i give power supply of 5v to ckt from arduino then arduino gets off.
i checked all my connections again and again.

This is the circuit

Did you connect the Pin 3 of LM339 to 5V and pin 12 to Gnd?

Did you ground all the unuse inputs of LM339?


//13 is the input to the circuit (connects to 150ohm resistor), 11 is the comparator/op-amp output.
// for guide

double pulse, frequency, capacitance, inductance;
void setup(){
	pinMode(11, INPUT);
	pinMode(13, OUTPUT);
	Serial.println("Why hello!");

void loop(){
	digitalWrite(13, HIGH);
	delay(5);//give some time to charge inductor.
	delayMicroseconds(100); //make sure resination is measured
	pulse = pulseIn(11,HIGH,5000);//returns 0 if timeout
	if(pulse > 0.1){ //if a timeout did not occur and it took a reading:
		capacitance = 2.E-6; //insert capacitance here. Currently using 2uF
		frequency = 1.E6/(2*pulse);
		inductance = 1./(capacitance*frequency*frequency*4.*3.14159*3.14159);//one of my profs told me just do squares like this
		inductance *= 1E6; //note that this is the same as saying inductance = inductance*1E6
		Serial.print("High for uS:");
		Serial.print( pulse );
		Serial.print("\tfrequency Hz:");
		Serial.print( frequency );
		Serial.print("\tinductance uH:");
		Serial.println( inductance );