Recent content by azra

"That's likely because there's a capacitor in parallel with the solar cell,so the capacitor charges slowly from the solar cell, but when discharged the capacitor can provide a high burst of current that gradually tapers down until at a long time short circuit you just get the continuous stream...

Thanks dlgoff! I used a 20k pot in series with a 8.2k resistor. I get the desired result (without using the solar cell) when I use Vcc (5V)to one end of the 8.2k resistor .But when I connect the solar cell and shine a light on it ( the voltage which should increase to about 3V-4V) changes...

Hi, I tried to use the voltage divider approach with a 5K pot. But at the output of the voltage divider ( analog input to the PIC) the voltage is very low like about 5mV. This is the way I connected it--> <positive end of Solar Cell>--><one end of 5K pot> <other end of...

Thanks Warren!

"Your PIC chip's ADC input pin probably has some "built in" resistance (ADC input resistance or input impedance on the data sheet)" Yes the maximum input impedance is 2.5k Thanks for your reply! I think I'll use the first two resistor voltage divider configuration you suggested...

"You mean the capacitors have one end grounded and the other end tied to the solar cell output?" Yes, you're right. I meant to say that the capacitors were in parallel with one end connected to the solar cell and the other end grounded. "What's the power supply voltage of the PIC?"...

"You didn't say what the sensor is or what the interface circuit is betweel the microcontroller and sensor." The microcontroller I'm using is a PIC16f877A.The light sensors in my circuit are solar cells (Part#CPC1822).I have connected 4 solar cells to four analog inputs (PortA pin 0,1,5,6)...

Hi, I am using a light sensor connected to an analog input of a microcontroller. My circuit turns an output high when there is a voltage of 2.5V or higher at the analog input i.e when there is a light shining on the sensor. But sometimes my output goes high even though I have no light shining...