FREE CIRCUIT DIAGRAMS 4U: Broken Charger Connection Alarm Circuit

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Electronic Circuit,Schematic Diagram,Circuit Diagrams

electronic circuit, circuit diagram, circuit schematic, schematic diagram, electronic diagram, audio, amplifier, power supply, guitar effect, current loop, current limiter, video, receiver, transmitter, transceiver, transistor, radio frequency, rf, active filters, digital, analog circuit, pwm, micro controller Free download

Friday, September 04, 2009

Broken Charger Connection Alarm Circuit

The above circuit can be useful to detect if the load of any battery charger or plug-in adapter supply is not properly connected. The load can be a set of batteries to be charged or any other type of battery or low dc voltage operated device. The circuit can safely operate over a 3 to 15V range and 1A max. Current, provided the supply voltage is about one volt higher than the voltage required by the load.The circuit is inserted between the supply and the load; therefore, until a trickle-charging current of at least 100µA is flowing towards the load, D1 and D2 will conduct. The forward voltage drop (about 1V) available across the Diodes drives Q2 into conduction and, consequently, Q1 will be cut-off. If no appreciable load is connected across the circuit's output, Q2 will become cut-off, Q1 will conduct and the Piezo-sounder will beep.

Parts:

R1 = 10K R2 = 1K R3 = 1K Q1 = BC557 Q2 = BC557 D1 = 1N4007 D2 = 1N4007 D3 = Red LED BZ1 = Piezo Sounder

Notes:

* An optional LED and its series limiting resistor can be wired in parallel to BZ1, as shown in dotted lines in the circuit diagram. * In this case you may omit the Piezo-sounder in order to obtain a visual alert only.