0 Simple Current flow indicator (electrical current)

This circuit will monitor if your input DC supply  is  delivering current to your battery or load. This is very simple and very easy to build since uses only  minimal parts.
current flow indicator
We have two working versions, one is using a NPN and other is PNP type of transistor.If your input DC supply is delivering current to your load, LED will light up while it stays off when no current flow or no load is connected. LED brightness is dependent on the magnitude of current, the larger the current the brighter the LED. You can use this circuit also to monitor if your charger is delivering current to your battery.

Part List:
LED - Red  or any low current LEDs
R1- 1.2 kilo-ohms 1/2W
NPN - 2N2222 or similar NPN transistor
PNP - 9012, 2N3906 or similar PNP transistor
R2 - value is dependent on the expected maximum current flowing in the load. See table below.
R2 vs expected current

Note: This current flow indicator is for DC supply use only and maximum input voltage is limited to 25V.


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