The operational amplifier (OpAmp/comparator) is used in this circuit to amplify the voltage. This is how the OpAmp works... the "+" input - the "-" input and multiply that by a large number such as 1000 will be the output. Or to put it simply... let "a" be the "+" input and "b" for the "-" input and "y" for the large number to multiply by and "z" be the output voltage... it will look like this: y(a-b)=z. The OpAmp will have a maximum voltage of usually 15 volts and a minimum of -15 volts. For this circuit it works by using a feedback. The "-" input is half the output due to the resistors. The way 2 resistors could change the voltage is by using this formula... For example, we will find the voltage out of resistor 2 (R2) ... this is the formula: R2(voltage/(R1+R2))=voltage across R2. Alright with half the output voltage going into the "-" input the voltage output will become twice the voltage going into the "+" input after it stabilises which is instant. You can try changing the circuit by increasing the value of the R1 resistor. The output voltage will be amplified by (R1+R2)/ R2 but remember about the maximum and minimum voltage. I do hope you understand how a OpAmp works and enjoy my creation. Please comment, bookmark and have fun. 😃
