Compact DC voltage detection module that safely measures 0–25V DC through a standard Arduino or microcontroller analog input. Uses a precision 30kΩ/7.5kΩ resistive divider to scale voltage down 5:1 — letting you monitor battery packs, solar panels, and power supplies without risk to your board. Screw terminals for secure wiring.
Specifications
| Brand | MH-Electronic |
| Input Voltage Range | DC 0 – 25V |
| Detection Range | 0.02445V – 25V |
| Divider Ratio | 5:1 (30kΩ + 7.5kΩ) |
| Max Input — 5V System | 25V |
| Max Input — 3.3V System | 16.5V |
| ADC Resolution | 10-bit (analog resolution 0.00489V) |
| PCB Size | 25 × 13mm |
| Mounting Hole | 3.0mm |
Wiring Reference
VCC (screw)Positive of the voltage source being measured
GND (screw)Negative / ground of the voltage source being measured
S (header)Signal output → connect to any analog input pin (e.g. A0) on your MCU
+ (header)MCU power → connect to 5V or 3.3V on your microcontroller
– (header)MCU ground → connect to GND on your microcontroller
Getting Started
| Arduino IDE | No library needed — use analogRead(A0) and apply the 5:1 scale factor in your sketch |
| Formula | Voltage = (analogRead / 1023.0) × Vref × 5.0 — where Vref is 5.0V or 3.3V depending on your board |
| ESPHome | Use platform: adc with filters: multiply: 5.0 to scale the reading |
| 3.3V systems | Change max input to 16.5V — adjust your formula accordingly |
Common Uses
Battery voltage monitoring — LiPo, Li-ion, lead-acid & NiMH packs
Solar panel & renewable energy output measurement
Under/over-voltage fault detection in circuits
DC power supply testing & data logging
DIY voltmeter with OLED or LCD display
Motor & actuator voltage monitoring in robotics
Frequently Asked Questions
Can this measure AC voltage?
No — DC only. The resistive divider cannot safely or accurately measure AC. For AC measurement you need a dedicated AC voltage sensor module.
Can I measure negative voltages?
No — the module is designed for positive DC voltages only. Applying a negative voltage to the input will damage the module and potentially your microcontroller.
What's the difference between the screw terminals and the header pins?
The two screw terminals (VCC and GND) connect to the voltage source you're measuring. The three header pins (+, –, S) connect to your microcontroller — power, ground, and the analog signal output pin.
Please note: Do not exceed 25V input on 5V systems or 16.5V on 3.3V systems. Measures DC only. The "+" header pin connects to MCU power — not to the voltage source. No display or microcontroller included.