Hi. I have a 7805 regulator circuit that drops 17 volts to 5 volts. When I connect 17 volts voltage supply, ı can read 5 volts at the output. I need to control a LCD circuit with pic16f877a microcontroller. When I connect my regulator to that circuit, the read 5 volts value drops to 3.2 volts and oscillates between 3.2V and 3.1V. So, I couldn not be able to light on my LCD. I think my capacitor values that on regulator circuit are not right. My regulator circuit does not give 5 volts when ı connect lcd circuit. but, it gives 5 volts when nothing connceted. what is my problem? thanks for your helps.