Hi all
Please help me, I would like this circuit to indicate up to 15 volts , what components should be added ?
**broken link removed** 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. Dont forget the forward voltage drop of the LEDs. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. Nonsense! The "designer" of this circuit has forgotten the forward voltage drop of the LEDs. The Vf of an LED depends on its colour and is not a well defined characteristic. Which makes this a bad circuit. 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. LED Volt Meter Circuit Circuit diagram:LED Volt Meter Circuit Diagram LED Volt Meter Circuit Diagram Author: D. Mohan Kumar Copyright: electroschematics.com [URL="http://www.extremecircuits.net/2010/06/led-volt-meter.html
]LED Volt Meter Circuit Diagram[/url]
Please help me, I would like this circuit to indicate up to 15 volts , what components should be added ?
**broken link removed** 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. Dont forget the forward voltage drop of the LEDs. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. Nonsense! The "designer" of this circuit has forgotten the forward voltage drop of the LEDs. The Vf of an LED depends on its colour and is not a well defined characteristic. Which makes this a bad circuit. 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. LED Volt Meter Circuit Circuit diagram:LED Volt Meter Circuit Diagram LED Volt Meter Circuit Diagram Author: D. Mohan Kumar Copyright: electroschematics.com [URL="http://www.extremecircuits.net/2010/06/led-volt-meter.html
]LED Volt Meter Circuit Diagram[/url]