Please Help!
Dear All,
I am new to this forum.
I am having some issues to measure current in low power devices. I have built a transimpedance amplifier (current to voltage converter) from the knowledge I obtained in some books and the internet. Amplification is necessary as my oscilloscope does not have enough resolution to capure sleep/standby events. I would like to observer what's happening by connecting it to an digital oscilloscope. However I am sure I missing something as I am not obtaining the expected results.
From the attached image you can see my current setup. I am using a single rail OPA335 opamp for the transimpedance amplifier. The output and ground are connected a multimeter. A +5V is supplied through a 220 ohm resistor and an LED (I also tried it without an LED). The non-inverting pin it connected to the '-' of the LED and the inverting pin to the supply ground.
The reading on the multimeter is completely off when testing with a 220ohm, 1K and 10K resistors.
Any help would be greatly appreciated.
Thank you in advance!
Dear All,
I am new to this forum.
I am having some issues to measure current in low power devices. I have built a transimpedance amplifier (current to voltage converter) from the knowledge I obtained in some books and the internet. Amplification is necessary as my oscilloscope does not have enough resolution to capure sleep/standby events. I would like to observer what's happening by connecting it to an digital oscilloscope. However I am sure I missing something as I am not obtaining the expected results.
From the attached image you can see my current setup. I am using a single rail OPA335 opamp for the transimpedance amplifier. The output and ground are connected a multimeter. A +5V is supplied through a 220 ohm resistor and an LED (I also tried it without an LED). The non-inverting pin it connected to the '-' of the LED and the inverting pin to the supply ground.
The reading on the multimeter is completely off when testing with a 220ohm, 1K and 10K resistors.
Any help would be greatly appreciated.
Thank you in advance!
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