Some info about current / voltage sensors
Current & Voltage Sensors
These are Integrated sensors that detect both the current, and the voltage (then, following Ohm’s law, the power) of a circuit.
The most common method for measuring currents in electronic circuits is to place low-value sense resistors in series with the load and measure the voltage drop across them.
INA219 High Side DC Current Sensor
This breakout board allows for power monitoring, including both a High side voltage and DC current draw sensor over I2C.
High-side and low-side current sensing refers to the placement of the current-sense resistor:
- High Side - between the positive supply and the load (whatever is being driven by the circuit);
- Low Side - between the load and ground.
- Vcc, power with 5V;
- SDA data pin;
- SCL clock pin;
- Vin- terminal (if you want to use another current sensor);
- Vin+ terminal (if you want to use another current sensor);
- Vin- of INA219 DC current sensor;
- Vin+ of INA219 DC current sensor;
- 1% precision;
- High Side measurement, up to +26V DC;
- Powered with 3-5V;
- Uses precision amplifier to measure voltage across 0.1Ω , 1% sense resistor;
- Can measure up to ±3.2A (since internal amplifier has maximum input resolution of ±320mV);
- Internal 12bit ADC( Analog to Digital converter);
- Resolution of 0.8mA at ±3.2A range.
This breakout requires the use of the library Adafruit INA219.
Now lets see a list of terms for the sensor:
- Bus voltage - voltage between GND and V-, total voltage seen by circuit under test. (supply voltage - shunt voltage);
- Shunt voltage - voltage between V- and V+, voltage drop across the shunt resistor;
Power sensor of a simple Circuit
We’ll be making use of all the basic functionalities of this breakout to do some simple measurements of a basic circuit!
Now, let’s see what our console should look like: