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Query about VU meters – I bought one today and tried it just now I am probably using some wrong parts check this out. https://www.youtube.com/watch?v=UbuRtk4uK9g. Look at the LEDs. They aren’t working properly. Read more

Designing discrete differential amplifier – I am trying to analyze a discrete differential amplifier circuit by answering some questions. I have done the analysis of the input stage and I would appreciate if I can get some feedback on my approach. Read more

Saturation current of inductor – I have black toroidal inductor cores. According to the manufacturer’s data, the saturation current is 3A Idc. If I use two cores for one inductor will its saturation current increase? Read more

Circuit not simulating buck converter – I am trying to build bunk converter as per tutorial video but where is the defect in the circuit? Read more

Power op amps application – I have used an 741 op amp with NTC temperature and comparator LM339. But what is power op amp application? Read more

AC sine wave to RCL circuit – I have noticed that when we connect the supply to a transformer there is back voltage/EMF generated which is higher than the applied voltage. It also depends on the frequency of supply and the capacitor value, inductor value, and resistance. Why does it happen? Read more

What the voltage on two ends of the balun – The source voltage is a ramp from 0V to 1V with Np:Ns=2:1. The source impedance Zg=100 and load impedance Zl=400. What’s the voltage of Vx and Vy given the input source voltage from 0 to 1V? Read more

Complimentary bidirectional switches –  I want to design a simple circuit using the cheapest components as possible. I want to have two complementary bidirectional switches. When the control voltage is 5V, one switch is open and the other is closed. When the voltage is 8V, the first one is close and the second open. Is it possible to design this circuit dirty= cheap using just transistors? Read more

Deriving transfer function for circuit – I need help with calculating my circuit, I’ve done something but not sure if that is correct. Any help or direction where to look at is welcome. In the end, I need transfer function of the circuit.

The first circuit is the one I start with, the second picture is “simplified” circuit with impedance for easier calculation.
Where
Z1=(1/Cin*s) + R1 + R2 + L1*s
Z2 = R3+L2*s
Z3 = L3*s
Zload = Rload + (1/C2*s) ?What I need is
uout/uin =
i1/uin =
i2/uin =
i2/i1 =
where uout is voltage on load and uin is entry voltage u1. Read more

50ns, 7V spike on power-up of 3v3 supply – I have an LMZ14201 buck converter circuit (3.3V dc output). The output is well-behaved when running. It has a soft start feature and ramps up very nicely. However, sometimes on power-up (perhaps 1 in 10), prior to the soft start circuit and exactly at the moment of energization, there is a short spike. Sometimes, there are two of them that last about 50nS at the 3.3V output. The peak voltage is about 7V. This circuit powers various digital ICs and I want to make sure they don’t get damaged from these 50ns spikes. The energy would obviously be quite low because of the short duration. Should I be concerned and add a TVS on the output, or are these spikes too short to be concerned about? When the spikes occur they are approximately where the red bar is in the first image. Read more