Discussion Overview
The discussion centers on the design of a voltage subtractor circuit that can produce an output voltage equal to the difference between two input voltages, specifically without the use of operational amplifiers (op-amps) and while functioning with only one positive supply. Participants explore various methods and historical approaches to achieve this goal.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- Warren initiates the discussion by asking for a circuit design that can subtract two voltages without using op-amps and questions historical methods used before op-amps were common.
- One participant suggests that reversing battery connections could illustrate voltage differences, but Warren clarifies that this analogy does not apply to his scenario with temperature sensors.
- Another participant proposes isolating one temperature sensor from ground to change connections, while Warren explains he can use separate ground voltages for the sensors.
- Warren describes a scenario where two sensors produce different voltages above their respective grounds and seeks a method to subtract these voltages to achieve a specific output.
- A participant raises questions about the intended precision, frequency range, and other specifications, suggesting a capacitor-based solution with FETs, but notes that it would be a discrete sampler with limitations.
- Some participants express skepticism about achieving the goal without op-amps, with one stating that passive components alone may not suffice.
- Another participant suggests that if the sensors could have floating grounds, a simple connection could allow for free subtraction, but acknowledges the need for a common ground.
- A participant introduces the idea of using a Wheatstone bridge to achieve the desired voltage difference, suggesting that it could be a viable solution.
Areas of Agreement / Disagreement
Participants generally disagree on the feasibility of designing a voltage subtractor circuit without op-amps. While some propose alternative methods, there is no consensus on a definitive solution, and several participants express doubts about the practicality of achieving the goal with only passive components.
Contextual Notes
Participants mention various assumptions regarding the use of separate ground voltages and the limitations of different circuit designs. The discussion includes unresolved questions about the precision and specifications of the proposed solutions.