Voltage level monitoring is essential in modern electronics to guarantee the correct operation of numerous systems and devices.
For real time voltage level visualization and measurement, a voltage level readout circuit is a crucial instrument.
In order to deliver accurate voltage comparisons and dependable readouts, this circuit makes use of the LM339 comparator IC.
LEDs, which act as visual indicators of voltage levels, and resistors which divide voltage, are the main parts of this circuit.
The circuit may function efficiently over a range of input voltages by using a 12V power source, which makes it appropriate for a variety of applications.
Because of its reputation for speed and low power consumption, the LM339 comparator is perfect for battery operated devices.
The circuit may separate the input voltage into controllable levels when resistors are incorporated, enabling the LM339 to compare the voltages to preset reference levels.
The matching LEDs light up in accordance with the comparators output states, giving a clear visual depiction of the voltage level under observation.
The basic ideas underlying the Voltage Level Monitoring Circuit are described in this introduction, along with an overview of its parts and features.
Users may improve performance and safety by putting this circuit into practice and learning a lot about their electrical systems.
Circuit Working:
Parts List:
| Component | Value | Quantity |
|---|---|---|
| Resistors | 1k | 4 |
| 560Ω | 4 | |
| 100k | 1 | |
| Semiconductors | IC LM339 | 1 |
| LEDs Red | Any 5mm 20mA | 4 |
This circuit is simple to construct on a typical PCB.
This design uses a voltage divider composed of identical 1k resistors to apply reference voltages.
This voltage divider and the power supply are linked to the non inverting terminals of the comparators.
If the voltage across all four of our 1k resistors is 12V, then the voltage across each resistor is 12V divided by 4 or 3V.
The input signal is linked to the four comparators inverting terminals.
The comparator output functions as a sink and activates the LED if the input signal is greater than the reference voltage.
Rather than the voltage source, the output is connected to the ground pin.
As a result, the load has to be linked between the comparators output pin and the supply positive terminal.
The LEDs anodes are connected to Vcc in this configuration, while their cathodes are connected to the output.
The input signal is connected to the inverting terminal, while the reference voltage is connected to the non-inverting terminal.
By connecting series resistors to R1 through R4, you may modify the reference voltage levels if the input voltage is lower.
Vt = Vcc – VR5 will be the total voltage across these resistors.
Formulas:
We may use the LM339 comparator IC to create a voltage level monitoring circuit.
The resistive voltage divider that will establish reference voltages at the comparator inputs has formulas and a summary of the connections below.
Reference Voltage :
The reference voltages at the comparator inputs using the voltage divider formed by the resistors R1, R2, R3, and R4.
Voltage at Pin 5 (Vref5):
Vref5 = VCC x (R2 / R1+ R2) =12V
Voltage at Pin 7 (Vref7):
Vref7 = VCC x ( R3 / R2 +R3) =12V
Voltage at Pin 9 (Vref9):
Vref9 = VCC x (R4 / R3+R4 ) = 12V
Voltage at Pin 11 (Vref11):
Vref11 = 0V (connected to GND)
How to Build:
To build a Voltage Level Monitoring Circuit using IC LM339 follow the steps below for connections:
- Gather all the components as shown in the above circuit diagram.
- Connect pin 1 of IC LM339 to cathode of LED2 through resistor R7 560Ω.
- Connect pin 2 of IC LM339 to cathode of LED1 through resistor R6 560Ω.
- Connect pin 3 of IC LM339 to positive supply of VCC +12V.
- Connect pin 4, 6, 8 and 10 of IC LM339 to +Vin input of the circuit.
- Connect pin 5 of IC LM339 between resistor R5 100k and resistor R1 1k.
- Connect pin 7 of IC LM339 between resistor R1 1k and resistor R2 1k.
- Connect pin 9 of IC LM339 between resistor R2 1k and resistor R3 1k.
- Connect pin 11 of IC LM339 between resistor R3 1k and resistor R4 1k and GND.
- Connect pin 12 of IC LM339 to GND.
- Connect pin 13 of IC LM339 to cathode of LED4 through resistor R9 560Ω.
- Connect pin 14 of IC LM339 to cathode of LED3 through resistor R8 560Ω.
- Connect all the anode legs of LEDs to positive supply of VCC +12V.
- Connect resistor R5 100k to positive supply of +12V and pin 5 of IC LM339
Conclusion:
This design concludes by showing how a voltage divider may be used practically to provide reference voltages for comparators using 1k resistors.
In order to efficiently regulate the LEDs lighting based on the input voltage, the circuit compares the input signal to these reference values.
The versatility of the circuit is further increased by the addition of series resistors, which allow the reference voltage levels to be changed.
Ultimately, this design is an accessible option for a range of electrical applications since it is simple to build on a PCB or dot board.
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