TREE

Here is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when fully charged. The LED voltmeter uses four Zener diodes to light the LEDs at the precise breakdown voltage of the Zener diodes. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. When the battery holds 13.6 volts or more, all the Zener breakdown and all LEDs light up. When the battery is discharged below 10.6 volts, all the LEDs remain dark. So depending on the terminal voltage of the battery, LEDs light up one by one or turns off. Circuit diagram:  LED Volt Meter Circuit Diagram Author: D. Mohan Kumar Copyright: electroschematics.com

This amplifier circuit or with it based on ic KA2210 main amplifier, audio amplifier circuit should disupplay minimum of 10 Volt and up to 16 volts. Power output is 2 x 5.5 W stereo amplifier att. By using this amplifier you can listen to the strains of songs from mp3 player, iPod, etc. This is schematic diagram Part List R1 = 4.7R R2 = 4.7R C1 = 1uF C2 = 100uF C3 = 47uF C4 = 100uF C5 = 0.1uF C6 = 1000uF C7 = 1uF C8 = 100uF C9 = 47uF C10 = 100uF C11 = 0.1uF C12 = 1000uF IC = KA2210