Discussion Overview
The discussion revolves around the design of a current to voltage converter circuit specifically for a silicon detector that produces a current of 10 pA. Participants explore various design methods, components, and considerations necessary for achieving accurate measurements at such low current levels.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Homework-related
Main Points Raised
- One participant suggests looking into electronmeter amplifiers, particularly transimpedance amplifiers, and recommends researching op-amps with low bias current.
- Another participant points out that the LTC6079 op-amp has a bias current of 1 pA, which may still be too high for detecting 10 pA accurately.
- Concerns are raised about the feedback resistor values needed to achieve the desired voltage output from the low current, indicating a need for a resistor in the range of 1 GΩ.
- A participant emphasizes the complexity of the topic, mentioning factors like noise, offset, drift, and settling that can affect measurements at such low currents.
- There is a discussion about the TL072IN op-amp, with one participant noting its input bias current is over 65 pA, which may not be suitable for accurately reading 10 pA.
- Questions are posed regarding the specifications of the current to be measured, including maximum and minimum current levels and accuracy requirements.
- Clarifications are sought on whether the 10 pA is a maximum current or a continuous measurement, and whether the focus is on measuring charge or current.
Areas of Agreement / Disagreement
Participants express differing opinions on the suitability of various op-amps for the task, with no consensus reached on the best approach or components to use for the current to voltage converter circuit.
Contextual Notes
Participants highlight limitations related to the specifications of the op-amps discussed, including input bias currents and accuracy requirements, which remain unresolved.
Who May Find This Useful
Individuals interested in circuit design, particularly in low-current applications, as well as students working on related projects in electronics or instrumentation.
