µCurrent Meter
µCurrent Meter
A micro current measurement meter adapter.
Connect to a multimeter to read out micro current on the voltage scale.
This design is based on the EEVBLOG uCurrent Original design, with extended measurement ranges, a better battery tester circuit, and it measures positive current only.
Applications: Measuring microprocessor sleep current, measuring RTC operating current.
Example
Let's say we want to measure microprocessor sleep current.
And assume the microprocessor will draw about 30mA while active and less than 1µA when sleeping.
- Connect the µCurrent Meter Adapter in series with the microprocessor power supply.
- Connect a voltmeter to the µCurrent Meter Adapter output, set for 5V (or higher) range.
- Set the µCurrent Meter controls as follows:
| Power switch | On |
| Battery Test button | Press to test, you should get a green light. |
| Range switch | 5000µA |
| Attenuation switch | 10X |
| Short switch | Off |
- Turn on the microprocessor power supply. The voltmeter will read 1mV/10µA, so it should show 3.0V for 30mA.
- Now the microprocessor goes to sleep.
- To measure the sleep current, change the µCurrent Meter settings as follows:
| Short switch | On for glitchless range switch change. |
| Range switch | 5000nA |
| Attenuation switch | 1X |
| Short switch | Off to restore current measurement mode. |
- The voltmeter will read 1mV/nA, so it should show 1.0V for 1uA. You can reduce the voltmeter range setting to get more resolution in the readout.
Specifications
Warning: Exceeding the maximum input limits may damage the device
- Maximum Input Limits: 5V maximum, 0.5mA on 5000nA scale, 500mA on 5000µA scale
- Output, 0-5000nA range: 1mV/nA (0-5.000V for 0-5000nA) or 1mV/10nA (0-5V for 0-50µA)
- Output, 0-5000µA range: 1mV/µA (0-5.000V for 0-5000µA) or 1mV/10µA (0-5V for 0-50mA)
- Terminals: 4mm Banana Jack
- Battery: (2) CR2032
- Dimensions: 68x88x20mm
Controls
| Power switch | Device power. |
| Battery Test button | Battery can be tested with power on or off. Green light will illuminate if the batteries are good. |
| Range switch | Selects the desired measurement desired range. |
| Attenuation switch | Use 10X attenuation to extend the measurement range. |
| Short switch | Shorts the current input terminals. Use when setting up or switching ranges for glitchless operation. |
Battery
Use (2) CR2032 batteries. Both batteries must be installed with (+) facing away from the circuit board.
Turn off power switch before replacing batteries. Double-check polarity before turning on.
Design Documents
| Bill of Material | ucurrent_bom.pdf |
| Schematic Diagram | ucurrent_schematic.pdf |
| 3D Print Files | ucurrent_mechanical.zip |
| PCB Gerbers | ucurrent_gerbers.zip |
Build Pictures
Front
Back
