Measure small currents without adding resistive insertion loss
https://www.electronics-lab.com/measure-small-currents-without-adding-resistive-insertion-loss/
by Maciej Kokot @ edn.com: In most cases, you measure current by converting it into a proportional voltage and then measuring the voltage. Figure 1 shows two typical methods of making the conversion. In one method, you insert a probing resistor, RP, in series with the current path and use differential amplifier IC1 to measure the resulting […]
Simple Acoustic Guitar Sound Receiver
https://www.electronics-lab.com/simple-acoustic-guitar-sound-receiver/
This design of acoustic sound receiver features low power operational amplifier. It has rail-to-rail input/output and 0.85mA supply current per amplifier. It uses piezo speaker as its microphone that can be attached to easily due to its size and dimension. The circuit is comprised of MCP6L91RT-E/OT 10 MHz, 850 µA operational amplifier that is used […]