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# Low Voltage Indicator

15 Threads found on edaboard.com: Low Voltage Indicator

## Lead acid battery - Minimum discharge voltage

THis sounds like an SLA type. All batteries rise in ESR rapidly as SoC gets low , which causes this apparent Load Regulation error. i.e. the ratio of source to load ESR. When equal voltage drops 50% when load is 9x ESR of battery voltage will drop (1/(1+9)) *100%= 10% and 10% of 12V is 1.2V drop. Thus a better indicator (...)

## understanding the schematics

IC4B just lights up some LEDs: D9 = normal operation; D10 = overcurrent condition (D11 it's an output voltage indicator). R19 (0.02ohm) is the current sense resistor. When the output current reaches 10A, the voltage drop across R19 is 0.2V so IC4A switches its output to low (IN+ of IC4A is adjusted to 0.2V in that (...)

You wish to measure AC current. Insert a low ohm resistor in the path. Read AC voltage across it. Current is calculated as V/R. The resistor should be sufficiently high that you can just get a sensible reading on it, but not so high that it heats up dangerously. That's the principle for quick temporary measurements. With some work you can duplic

## low voltage battery indicator circuit

hello everybody, please i need a low voltage battery indicator, and the battery to be 9v, or 3v, to indicate a red led when the battery gets down under the 9v or the 3v, and please i need reliable circuit " one when make to work for sure", cause i got many from google and when simulated on proteus, never worked, so hope i get a serious (...)

## L6920 Low voltage indicator LED does not work

I 've made a boost converter with L6920 As you can see in the image, at LBO pin I've put the cathode of the LED. LBO is an open drain output, which goes low (does that mean it gets grounded???) when the battery voltage goes below the treshold we h

## LVCO and low battery indicator

I'm trying to both protect a two cell LiPo pack and also indicate to a human when the pack is getting low. I chose to use a pair of voltage supervisors due to their low current consumption. One kills the system when the voltage drops to roughly 6.2V, simple enough. The other is used to switch from a green LED to a red LED (...)

## Battery charger working.

Anybody know working of this circuit???77864 This is a circuit diagram of an indicator + 2 Amp charger to sense/charge battery of 12 volts. Working principle of this circuit is the battery voltage compared with the reference voltage. By using the LM324 IC, which is a low Power Quad Ope

## 2 power supply LED power indicator

just put a diode in the dc source arm , see the pic below 74011 well , you have not mentioned the ac power level , if it is low you can use 1N4007 diode or find some proper rating diode ... Hope it helped :)

## Low battery Indicator

A Simple add-on circuit that can be connected to most occasionally used 9V battery-powered equipment to give a low battery warning is shown in Fig.. It is simply connected to the circuit so that it is powered up when the main circuit is turned on. With a new battery, the l.e.d. D1 should light briefly. This period will get progressively longer unti

## resistance to voltage converter

It would be interesting to know what is the indicator resistance at 10% water level. My idea is that near the very low water level the indicator becomes nonlinear or at certain low level is opencircuited. Maybe the usefull range of indicator doe not need to be up tu 35Mohms and the indicator (...)

## Charge level indicator for li-pol 7,4V

It’s unfinished project of Lama V4 heli. The problem with that model is a diode that indicate low battery level, which is poorly visable. To have long fun with power package, you need to keep voltage limit per cell – a

## RS485 driving me crazy

We have an installation with around 70 units with a PIC16f648 driving a low power rs584 chip. These run via a a central 12v psu. Each unit has onboard 5v reg, filtering and surge suppression and is wired in various star and series configuration. These transmit back to a single receiver in an indicator panel. voltage is down to about 7v at (...)

## RS232 LED status indicator circuit

i think when Dout or Din are low then you will get respective LED ON.

## Solution for Phone-In-Use indicator

You have to sense the voltage on the line. If the modem is using the line the voltage will be low 11-17VDC. If the line is available, the voltage will be around 48VDC. So your circuit could easily lockout the phone by activating a relay when the modem is in use.

## How to design a over power protect circuit???

maybe you can let heat be your wattage indicator, like a resettable thermal fuse mounted on the heatsink that shutsdown the supply if open, or a thermal resistor that pulls an enable pin low when its hot enough