• Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Get free circuit help 24/7

New Projects | Privacy Policy | About Us | Contact | Disclaimer | Copyright | Videos 

Op Amp Basics | 555 Circuits | Hobby Circuits | LED Driver | For Beginners | Basic Circuits | Transistor Circuits | Voltage Regulators 

You are here: Home / Sensors and Detectors / IC 555 Low Battery Indicator Circuit

IC 555 Low Battery Indicator Circuit

Last Updated on September 9, 2023 by Swagatam 55 Comments

The article explains a simple low battery indicator circuit using the IC 555 and a few resistors only.

Table of Contents
  • Circuit Concept
    • Circuit Operation
      • Simple low battery indicator circuit using IC 555 Diagram is shown below:
      • Parts List
  • 555 Low Battery Indicator with Flasher

Circuit Concept

Many electronic circuits such as emergency lights,  battery chargers, UPS systems, flashlights etc essentially require a low battery indication feature in order to avoid over discharge of the involved battery. An over discharge could mean a permanent damage to the battery.

A novel little low battery indicator circuit can be learned here, which incorporates just a single IC555 and a few resistors, it's a simple "plug and watch" kind of circuit.

Circuit Operation

The circuit functioning may be understood with the following points:

We all know regarding the basic characteristic of the IC 555 when it's being used in the comparator mode: if pin#2 is subjected to a potential lower than 1/3rd of the Vcc, the output pin#3 goes high.

The above fact also indicates that pin#2 responds with reference to the supply voltage applied at pin#8 of the IC, which implies this voltage at pin#8 should be clamped to some constant level.

Therefore in the proposed design the supply pin of the IC is fixed at some reference level using a zener diode.

The battery voltage is allowed to reach pin#2 of the IC via the preset, which must be manually set such that voltage at pin#2 just falls below the 1/3rd of the zener voltage when the battery voltage reaches the specified lower threshold.

The above setting can be done manually by applying a sample voltage to the circuit imitating the lower threshold level.

Suppose, the specified lower threshold is 11.4V for a 12V battery, the applied sample voltage can be fixed at 11.4V and applied to the circuit. Next, the preset should be adjusted such that the LED just lights up. Now the preset may be glued by some permanent adhesive for preventing the setting from getting disturbed.

The set circuit is now ready to be attached with the battery in question, whenever the battery voltage reaches the 11.4V mark, the LED would light up, providing the required low battery information.

Simple low battery indicator circuit using IC 555 Diagram is shown below:

caution electricity can be dangerous

Parts List

R1,R3 = 10K
R2 = 100K
IC1 = 555
P1 = 100K preset
Z1 = zener diode, having voltage lower than the battery voltage.

IC 555 Pinout

555 Low Battery Indicator with Flasher

This 555 low voltage indicator circuit is designed to activate an LED when the power supply voltage exceeds a specific threshold and to make it flash when the batteries require replacement.

The provided component values are optimized for a 9 V operation. The flashing function initiates at approximately 7.5 V, while the LED won't illuminate at all below 2 V.

The circuit comprises a 555 timer configured in the bistable mode, serving as the driving mechanism for the LED.

The key element here involves connecting a zener diode between pin 7 of the 555 timer and the ground.

During standard operation, pin 7 oscillates between one-third and two-thirds of the supply rail voltage (Vcc). If the voltage at 2/3 Vcc exceeds the zener voltage, it inhibits the 555 timer's functionality.

To adapt this circuit to your specific needs, determine the minimum voltage necessary for proper equipment operation and multiply it by 2/3 to obtain the required zener voltage.

Additionally, you may need to adjust the resistor (R) to match the particular LED you intend to use.

In its original configuration, this indicator circuit drew 7 mA of current at 9 V, decreasing to 5 mA at 7 V.

If these values are potentially problematic for your application, consider using the CMOS variant of the 555 timer, the 7555.

You'll also like:

  • 1.  Electric Match (Ematch) Circuit Firework Ignitor
  • 2.  Ultrasonic Motion Detector Circuit
  • 3.  IC 555 Pinout Working with Formulas
  • 4.  RPM Controller Circuit for Diesel Generators
  • 5.  Simple Transistor Diode Tester Circuit
  • 6.  Simple Soil Moisture Tester Circuit with a Single IC 741

About Swagatam

Swagatam is an electronic engineer, hobbyist, inventor, schematic/PCB designer, manufacturer. He is also the founder and the author of the website: https://www.homemade-circuits.com/, where he loves sharing his innovative circuit ideas and tutorials.
If you have any circuit related queries, you may interact through comments, and get guaranteed replies from the author.

Have Questions? Please Comment below to Solve your Queries! Comments must be Related to the above Topic!!

Subscribe
Notify of
55 Comments
Newest
Oldest
Inline Feedbacks
View all comments


Primary Sidebar

Categories

  • 3-Phase Power (15)
  • 324 IC Circuits (19)
  • 4017 IC Circuits (52)
  • 4060 IC Circuits (27)
  • 555 IC Circuits (99)
  • 741 IC Circuits (20)
  • Arduino Engineering Projects (83)
  • Audio and Amplifier Projects (126)
  • Battery Chargers (83)
  • Car and Motorcycle (96)
  • Datasheets (78)
  • Decorative Lighting (Diwali, Christmas) (33)
  • Electronic Components (101)
  • Electronic Devices and Circuit Theory (36)
  • Electronics Tutorial (121)
  • Fish Aquarium (5)
  • Free Energy (34)
  • Fun Projects (14)
  • GSM Projects (9)
  • Health Related (22)
  • Heater Controllers (31)
  • Home Electrical Circuits (107)
  • How to Articles (20)
  • Incubator Related (6)
  • Industrial Electronics (28)
  • Infrared (IR) (40)
  • Inverter Circuits (98)
  • Laser Projects (13)
  • LED and Light Effect (98)
  • LM317/LM338 (22)
  • LM3915 IC (25)
  • Meters and Testers (69)
  • Mini Projects (150)
  • Motor Controller (69)
  • MPPT (7)
  • Oscillator Circuits (25)
  • PIR (Passive Infrared) (8)
  • Power Electronics (35)
  • Power Supply Circuits (86)
  • Radio Circuits (10)
  • Remote Control (50)
  • Security and Alarm (66)
  • Sensors and Detectors (131)
  • SG3525 IC (5)
  • Simple Circuits (75)
  • SMPS (29)
  • Solar Controllers (63)
  • Timer and Delay Relay (55)
  • TL494 IC (5)
  • Transformerless Power Supply (9)
  • Transmitter Circuits (42)
  • Ultrasonic Projects (17)
  • Water Level Controller (45)

Calculators

  • AWG to Millimeter Converter
  • Battery Back up Time Calculator
  • Capacitance Reactance Calculator
  • IC 555 Astable Calculator
  • IC 555 Monostable Calculator
  • Inductance Calculator
  • LC Resonance Calculator
  • LM317, LM338, LM396 Calculator
  • Ohm’s Law Calculator
  • Phase Angle Phase Shift Calculator
  • Power Factor (PF) Calculator
  • Reactance Calculator
  • Small Signal Transistor(BJT) and Diode Quick Datasheet
  • Transistor Astable Calculator
  • Transistor base Resistor Calculator
  • Voltage Divider Calculator
  • Wire Current Calculator
  • Zener Diode Calculator

© 2023 · Swagatam Innovations

wpDiscuz