Build Your Own 9V-12V Low Voltage Alarm Circuit

Description

This modest voltage circuit is designed for observing batteries and fluctuating power sources for potential difficulties. The circuit triggers an alert and illuminates an LED, but it can be connected to a vast array of other circuits for diverse applications.

Circuit diagram

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LM339 Voltage Comparator IC

The LM339 is a versatile operational amplifier integrated circuit that is frequently utilized as a voltage comparator. It’s a three-terminal IC – positive supply (V+), negative supply (V-), and output (OUT). The LM339 effectively compares two input voltages and outputs a digital signal indicating which voltage is higher. This makes it ideal for applications such as voltage level detection, triggering circuits based on voltage thresholds, and creating comparator circuits for various sensor measurements. It’s characterized by its high input impedance, enabling accurate comparisons even with relatively low input voltages. The LM339 typically operates with a supply voltage of ±15V, although it can be configured for single-supply operation with appropriate external components. It's a robust and widely-used IC renowned for its reliability and performance in comparator circuits.

Security Warning

Working with electrical circuits involves potential hazards. Always exercise caution and follow proper safety procedures. Disconnect power before making any changes or adjustments. Improper handling of electrical components can result in serious injury or damage to equipment. This circuit diagram is provided for informational purposes only and should not be considered a substitute for professional advice. The author, Robert Williams, takes no responsibility for any damages or injuries resulting from the use or misuse of this circuit. The source of this diagram is Electronics Hobbyist Magazine, Vol. 12, Issue 4.