#Low battery indicator circuit series#

The above circuit has an issue and may not work as intended, because the left LED would be always ON due to the conduction via the right hand side BC547 emitter. The results obtained are identical, the left LED illuminates when a low voltage is detected, until this happens the flasher LED keeps blinking indicating a normal operation of the battery. Here we find a third BJT being added to the existing stage, which holds a multicolor RGB flashing LED for the required indications (the same may be replaced with a simple LED if the flashing effect is not required).

Until the set lower threshold is not reached, the above pin of the IC is allowed to receive the specified amount of positive potential sustaining the green LED in a blinking mode, which in turn indicates that everything is well with the battery.įor lower voltage applications, the IC 555 stage may not function correctly since its minimum operating voltage is 4.5V, under such conditions the following configuration could be tried.

#Low battery indicator circuit series#

The IC 555 is wired in its conventional astable mode so that the connected green LED produces a flashing effect as long as its reset pin#4 stays above a certain positive voltage level via the red LED and the series 10k resistor.

The low battery stage produces only a low voltage indication and the relevant LED shines only until the level dips below the set threshold, this might well keep the user guessing if the actual or the normal condition of the battery was OK and if the battery was functioning correctly in the meantime.įor satisfying the above results, a flashing LED indicator could be seen attached with the low battery section, using our old compatriot IC 555. This stage has been elaborately explained HERE, you may want to go through it for further details. The left side stage which uses two BJTs is a simple low battery indicator circuit, the red LED lights up as soon as the supply voltage falls below the predetermined threshold level, as set up by the 47K preset. The figure below shows the circuit configuration of the proposed battery voltage status indicator circuit through a flashing LED indicator. Is there any way to add a second LED that will flash to indicate power is there and working? The low battery indicator circuit is working fine but I have to put my meter across the terminals in order to check it is still working. On your website because I am growing vegetables in a raised bed and have erected 12v electric fence to prevent slugs and snails eating my plants.įor this I am using an old car battery which is holding a good charge.

Hi, I found and built your “ Low Battery Indicator Circuit Using Two Transistors Only”