TekPower TP4000ZC PC based RS232-Interaced Auto Ranging Digital Multimeter for $29.99

The Tekpower TP4000ZC is a digital multimeter with a RS232 interface, via which you can connect your PC to monitor the real time measurement and also plot and save your data on your computer. This meter is auto/manual range selectable, you can use it to measure a wide range of parameters including AC/DC voltage and current, as well as resistance, capacitance, frequency and so on.