11 hours ago
- Resistance is the opposition to current flow; in resistors, it is constant and follows Ohm's law (I = V/R).
- Differential resistance measures local response to small voltage changes and can be negative in certain V-I curve sections.
- True negative resistance (constant negative R) is impossible without an external power source, as it would imply energy generation.
- A practical circuit using an op-amp can simulate constant negative resistance by feeding current back into the source.
- Negative differential resistance (NDR) occurs when increasing voltage leads to decreasing current in part of the V-I curve.
- The lambda diode, made with two complementary JFETs, exhibits NDR without needing an external power supply.
- Snapback behavior is another form of NDR where increasing current causes a sudden drop in required voltage.