Pulsing battery charge indicator

147

02:06:38

LED pulses if input supply voltage is less then or equal to 12 volts if input is greater then 12 volts LED stays on power charge is good 

adjust the input voltage to 12 volts or less to see LED flash battery not charging 

Have not tested 

published 11 years ago

Sine_eyed

11 years ago

It works- this is a good little circuit imo. The lower cut-off is at 3&2/3V, meaning it starts oscillating at 3.68V. At the other end it's solid on at 12&2/3V. That two thirds thing- must be in the biasing. I assume that whatever device is being monitored, isn't going to go much higher than 12 volts, so a 560 ohm current limiting resistor is probably all that's necessary. The clock is set pretty low, so you could bring that up a bit- but I like how the frequency follows the declining voltage. Nice one..

Sine_eyed

11 years ago

Ah, a car battery ok. That's the kind of information (along with most everything else you just said) that goes perfectly into a description! Maybe next time..

Sine_eyed

11 years ago

About the other stuff: I think the frequency variance is ok where it is-- I was talking about the current limiting resistor for the LED-- So it's the 12V zener tied to the base of the first transistor in the oscillator that that stops it from oscillating after it gets to 12V then? I never would have guessed that.-- And I don't read textbooks, because most of them were written by the devil. '°;.;°'

jamilfaultfinder

11 years ago

Thank you for your feedback

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.