Voltage Level Indicators for battery Using LM324

This circuit diagram represents an indicator designed to display a battery voltage of 12 volts. The working principle involves comparing the battery voltage with a reference voltage using the LM324 integrated circuit, which is a low-power quad operational amplifier. The circuit utilizes a single IC chip for its operation. The output from the operational amplifier is connected to C9013 transistors, which function as switches to control the illumination of LEDs. The voltage level is indicated by four LEDs arranged in a vertical array for better visibility. The top three LEDs are green, while the bottom LED is red. As the battery voltage decreases due to usage, the LEDs will sequentially turn off from top to bottom. When the battery voltage drops below 11.83 volts, only the red LED will remain lit, indicating that the battery is low. The red LED will turn off when the voltage falls below 11.5 volts.

The circuit operates by leveraging the LM324 operational amplifier, which is configured in a comparator mode. The reference voltage is set using a voltage divider network that establishes a threshold for the battery voltage. The output from the LM324 is connected to the base of the C9013 transistors, which are configured in a common-emitter arrangement. This configuration allows the transistors to act as switches that control the current flowing through the LEDs.

The four LEDs are strategically positioned to provide a clear indication of the battery voltage status. The green LEDs correspond to higher voltage levels, indicating that the battery is in good condition. As the voltage drops, the operational amplifier's output changes state, causing the transistors to turn off the green LEDs while turning on the red LED when the voltage falls below the specified thresholds.

The circuit is designed to be simple yet effective, providing a visual representation of battery health. It is suitable for various applications where monitoring battery voltage is essential, such as in battery-powered devices and solar power systems. The use of the LM324 IC ensures low power consumption, making this circuit efficient for continuous operation. Proper heat dissipation should be considered for the transistors to ensure reliable performance over time.This circuit is a circuit diagram of an indicator to show battery voltage 12 volts. Working principle of this circuit is the battery voltage compared with the reference voltage. By using the LM324 IC, which is a type LM324 Low Power Quad Operational Amplifier, so that the circuit this time is to use a single IC chip. The output of OP-amp, then con nect with the C9013 transistors, these transistors act as switches to turn on and turn off the LED. Voltage level indicated by four lights led. For ease of reading led arranged in a vertical array. Selected the top three headed green LED while the lower was the most selected red color. If the battery voltage continues to decline (because of usage), then-Led Led will die in sequence from top to bottom. Until the battery when the voltage is below 11. 83 volts then the red led light only means that the battery charges. Red LED will die if the program continues until the voltage falls below 11. 5 volts. The following is a schematic drawing: 🔗 External reference