The voltage sensor module is a small size 0-25 DC voltage sensing device. The design of the module is based on a resistive voltage divider circuit. It is a voltage sensor module that reduces the input voltage signal by the factor of 5 and generates a corresponding analog output voltage with respect to step down voltage factor.
This voltage measurement circuit is small and portable and can be used to detect under and over-voltage faults in electrical circuits. 
Features & Specifications
Input Voltage: 0 Volts – 25 Volts
Voltage measurement Range: 0.02445 Volts – 25 Volts
Analog signal resolution: 0.00489 Volts
Voltage Sensor module dimensions: 4cm x 3cm x 2cm
It is a small, portable and reliable device.
The module is a simple circuitry and easy to interface with Arduino microcontrollers.
 
Pin
Function
VCC
Positive power supply pin. The positive terminal of the power supply to be measured is connected to this pin.
GND
Reference potential pin. It is connected to the negative terminal of the power supply.
S
Analog output pin voltage of sensor. Connect it to the analog input pin of Arduino or any other microcontroller which you want to use.
+
Not connected
–
Ground connection pin. It must be joined to the ground pin of the Arduino or microcontroller and also to the power supply ground pin.