Sergei Bezrukov writes:
This is a shortened translation from Russian of my article published in Радио (Radio) magazine, no. 12 (2009) pp. 18-21. The micro-ampermeter described here is intended for experimenting with low-power devices. I have just a general multi-meter in my home lab, which is not very convenient to use. The reason for this is that now-days many electronic devices have a power saving mode, where their current consumption drops down in 1-3 orders of magnitude. Measuring current in a device that periodically enters a sleep mode makes it necessary to frequently adjust the multi-meter range, unless it is automatic. Unfortunately, my multi-meter is not automatic. Moreover, I often need to measure current along with voltage, which makes working with my measuring device even more inconvenient.
The micro-ampermeter described here has the following features:
- Monitoring current range: 0.05μA – 10mA
- Four subranges: 0.05μA – 9.99μA, 10μA – 99.9μA, 100μA – 999μA, 1ma – 9.99mA, automatic range switching.
- Voltage drop: 82mV max
- Automatic shutdown after approx. 3 minutes of inactivity
- Battery operation from 2xAAA batteries, average drawing current 10mA
Automatic micro-ampermeter - [Link]