Can R Thevenin be negative?

We assume that there are no negative-valued resistors (of the type you find in your lab kit, for example). However, when modeling a circuit that contains dependent sources, it is possible that the Thevenin Equivalent resistance is negative.

What happens to dependent sources in Thevenin?

Thevenin’s theorem can be applied when analyzing a circuit with dependent sources. In this case, all independent sources are turned off and the RTh is calculated by applying a current source or voltage source at the open terminal. When using a voltage source, it can be assumed to be 1V for simple calculations.

Is the time constant negative?

exists. However, when talking about a transfer-impedance, excitation at some point and response at a distant point, a time constant can be negative. In the Fourier world, at some frequencies the excitation and the response can be in opposite phase due to the runtime between the two points.

What does negative resistance mean?

In electronics, negative resistance (NR) is a property of some electrical circuits and devices in which an increase in voltage across the device’s terminals results in a decrease in electric current through it. They are used in electronic oscillators and amplifiers, particularly at microwave frequencies.

Can you have negative resistance in a circuit?

Negative Resistances is a behavior in which the current and voltage are inversely proportional to each other. A normal circuit with a resistor following ohm’s law has a current drop, when the voltage decreases. In case of a negative resistance, the current increases with a voltage drop.

What are dependent and independent sources?

Independent source are those, whose value of either the voltage or the current to be delivered is independent of any other parameter of the network. Where as the dependent sources are those, whose value of either the voltage or the current to be delivered is dependent or controlled on other parameters of the network.

Why do we need dependent sources?

Dependent sources are useful, for example, in modelling the behavior of amplifiers. A bipolar junction transistor can be modelled as a dependent current source whose magnitude depends on the magnitude of the current fed into its controlling base terminal.

Why do we use dependent sources in circuit analysis?

Dependent sources are not “off-the-shelf” items in the same way that a battery is. Rather, dependent sources usually are used to model the behavior of more complex devices. For example, a bipolar junction transistor commonly is modeled as a CCCS while a field effect transistor may be modeled as a VCCS1.

Why does my Thevenin equivalent circuit have negative resistance?

It’s very common for Thevenin equivalent circuits to have negative resistance when there are dependent sources in the network. I can post an example later if it would help (I’m typing on my iPhone at the moment).

What is Thevenin’s theorem in DC network analysis?

Chapter 10 – DC Network Analysis. Thevenin’s Theorem states that it is possible to simplify any linear circuit, no matter how complex, to an equivalent circuit with just a single voltage source and series resistance connected to a load.

How to calculate Thevenin’s voltage?

Solution: 1 Remove the 5 kΩ from the circuit. 2 Measure the open-circuit voltage. This will give you the Thevenin’s voltage (V TH ). 3 We calculate Thevenin’s voltage by determining the current that flows through 12 kΩ and 4 kΩ resistors. 4 Short the voltage sources as shown in the figure below:

What is Thevenin’s theorem used for in source modelling?

Thevenin’s theorem is used in source modelling and resistance measurement using the Wheatstone bridge. Thevenin’s theorem is used only in the analysis of linear circuits. The power dissipation of the Thevenin equivalent is not identical to the power dissipation of the real system. What is Thevenin’s Theorem?