In the circuit we have four 1kΩ resistors, the voltage across each resistor will be equal to Vcc/4. The voltage divider is connected across the supply and each point is connected to the non-inverting terminal of the comparators. Here the reference voltages are obtained by using a voltage divider network of equal resistors (1kΩ). So, we can use up to 4 reference values to compare to check whether the input voltage is above or below the 4 reference points. The main component of this voltage level indicator circuit is an LM339 IC which is a quad comparator IC that has 4 comparators. If we exchange the above voltage values between two inputs then the inverting terminal will have the larger value and then the output will switch to a LOW state. Then the output becomes high as the voltage at the non-inverting terminal has a larger value. It simply checks the voltage between two inputs and gives an output either high or low irrespective of the magnitude of difference between them.įor example, if the input voltage at non-inverting ( + ) = 6V, input voltage at inverting ( – ) = 5.8V. And the output switches to a low state or negative saturation when the input voltage at the inverting terminal is larger than the non-inverting terminal. The output of the comparator will be in a high state or positive saturation when the input voltage at the non-inverting terminal is larger than the voltage at the inverting terminal. The two inputs of the comparator are inverting ( – ) and non-inverting ( + ) inputs. The voltage level indicator circuit given here uses a comparator circuit to compare the input values to check whether the input is above or below the reference value.Ī comparator is a device that compares two inputs and produces an output that indicates which input is larger. Because the input value is above the reference point 3V & 6V but below 9V & 12V. If we apply an input voltage of 8V then the LED 1 and 2 becomes ON and the LED 3 and 4 remain OFF. Usually, the circuit consists of a sequence of threshold points with the corresponding sequence of LEDs arranged to light ON when the input voltage reaches equal to or above each threshold values.įor example, the reference points of a voltage level circuit are 3V, 6V, 9V, 12V, and the corresponding LEDs are LED1, LED2, LED3, LED4 respectively.
A voltage level indicator is a circuit that can be used to indicate the voltage range of input supply.
0 kommentar(er)
