we know voltage divider bias circuit gives the fraction of the input voltage.i seen in a book that with choosing any one of the resistance has negative ,we achieve amplification.what does that negative resistance mean.how does it affect the circuit.explain me basically

Can anyone help me find the input resistance of the circuit? I have been stuck for many hours and can't solve it.

I find the equivalent resistance of the circuit by applying a voltage source at the input and solve for the current I.

The input resistance:

Rin = V/I

However, I don't know why this method doesn't work.

I do not know how to find the value of the series resistor(Rs) because there are many variable. It is hard to decide which current(knee/maximum) or voltage should I select . Can some one teach me??

Question:
Given that the zener voltage Vz = 8.2V, with the condition that the zener current 75mA ≤ Iz ≤ 1A and the load resistance RL = 9Ω.

I need a pulse generator to drive a plating cell which has a resistance of roughly 1-2 ohm. I want to drive it with a squire pulses with the frequencies in the range of 1-60Hz and fixed current of 5-10A.
I want to use Arduino that will drive a MOSFET via octocoupler and a linear regulated 30V, 20A DC power supply. The circuit diagram is attached.

Hi everyone,

I am a bit confused about the operation of a boost converter, mainly with the changing current. In the attached image I replaced the diode with a switch. Now I keep reading that once the turn my W1 switch off and turn on my W4 switch the current will decrease and the voltage will drop.

Howdy Guys -

I'm in a basic circuit analysis class. I'm having difficulty consistently calculating Thevenin's equivalent resistance.

i just reading an analogy for Ohm's Law about current and voltage, but i still didn't understand clearly "With resistance steady, current follows voltage (an increase in voltage means an increase in current, and vice versa)". it is say that when voltage increase so the current increase too with resistance steady.

i means that in practically. for ex.

If you have a power supply and you limit its current, while wiring two resistors of different values in parallel to the power supply, would this limited current make it such that the voltage across the larger resistor is 0V because current tends to take the path of least resistance?

I'm curious and don't have this kind of power supply to test but here are 3 cases and what I'm thinking:

Schematic

I do understand the equations behind biasing a MOS over a drain-gate resistance, but why is this resistance usually in the MOhm range?

As there is no current flowing into the gate would it not matter how big or small the resistance is?