Powering the emonTx
CT Energy Monitoring
Current Only (Apparent Power)
Voltage and Current (Real Power)
Reading Directly from Utility Meters
The emonTx has inputs to connect multiple DS18B20 one-wire digital temperature sensors. By default these sensor are powered from the 5V line (supplied from the USB) if powering the board from the 3xAAA battery holder the 3V and 5V power rails should be connected together to enable the sensors to be powered from 3.3V. This can easily by done by jumpering the 5V and 3.3V on the JeePort.
Caution: This jumper should be removed before a usb connection is plugged into the board. No voltage greater than 5.5V should be connected to the Aux input when DS18B20 temperature sensors are connected.
emonTx SMT Prototype V0.6 rev 1 Testing
Questions to Answer:
- Can a 0603 resistor supply enough current to the LED's 1/16W=62.5mW = 18.9mA MAX @ 3.3V. Give a 1.8 Vf LED 10mA with a 160R resistor 16mA through Resistor = safe but will LED be bright enough?