# Recent content by hardings

1. ### Help me! How to solve the phase margin problem for this op-amp

If decreasing DC gain is permitted, why not just remove the 2nd stage, that will overcome all of your problems.
2. ### asking help for solving a simple cmos problem

Gain=10 only, why do you use this structure?
3. ### How to design a Voltage Averaging Circuit with low current

If V0,V2 is dc voltage, just use 2 resistors. If V0,V2 is ac signal, use filter first? I am not sure.
4. ### Reference current source circuit?

Hi, We know we have bandgap for accurate reference voltage, but is it possible to implement some kind of circuit as reference current? Of cource do not use reference voltage over resistor simply which is resistor value dependant.
5. ### Formula for SMPS transformer calculation

smps transformer design Good question! I think Picstudent is talking about flyback transformer. Hope someone here can explain the most reasonalbe design for flyback transformer. The question can be more exact if we take 5V/1A output design as an example. Added after 2 minutes: Here is...
6. ### Questions about Class-D output stage

Can you post some drawing to help the helper?
7. ### Help me find the output impedance of a circuit

gain-boosting VG is not zero, why you think vg is 0? Only when VB=VX, VG is zero, but here VB=0, VX is not 0.
8. ### Help me find the output impedance of a circuit

gain-boosting I think Vgs is not equal to A1Ve, A1Ve is the AC voltage from Vgate to GROUND. Vgs is the AC voltage from Vgate to Vx Now you can finish your calculation.
9. ### Help me to understanding this

Something wrong in your circuit, the 1st input stage?
10. ### Help me find the output impedance of a circuit

gain-boosting But you are analysing AC character, not DC. For source degeneration, Vin is a dc level voltage, in other word, vin is ground for AC analyse.

So you follow the latest step by communicating here?
12. ### Help me find the output impedance of a circuit

gain-boosting Ve=Vx, and then do KCL for node X, For learning, you can use this way. but for designing, use barath_87's way.
13. ### What exactly is a Dead Zone Circuit?

Dead Zone Circuit Something wrong in the circuit. I guess the deadzone means some diodes are not forwarded.
14. ### Help me find the output impedance of a circuit

gain-boosting I guess it is because of the input, one terminal of VIN should be connected to RO1?