Posts by Andy aka
In the absence of VNA product documentation...... Now, -9 dB is equivalent to a ratio of 0.34 approximately, and -3.53 db is equivalent to a ratio of 0.66 approximately. I expected S11 to be nea...
It was my understanding that the advantage of a pi filter would be the symmetrical nature, where signal direction does not matter. and What would be a reason to decide to use non-symmetrica...
How does this work - how does it improve THD performance? As with any transformer connected to a live wire, there will be an AC voltage common mode signal transferred by winding capacitance to...
If so, how would that work without a source resistor? Quite well actually. If you look at the 2SK1109 you'll see that it has this characteristic: - I've highlighted the zero voltage bias po...
are there more elements contributing to this effect that I have not placed in the circuit? Well, you have a simulator and it should be really easy to remove C_windings and observe if the ringi...
Why are CY capacitors on the source side, and not on the load side? You may not be grasping what the image shows. The left-side port connects to the AC power-line. It supplies power to the rig...
Has anyone else noticed a loss of reputation recently. I thought I checked yesterday and my reputation was a hundred points higher at 1889. Now it is at 1789. My vote summary doesn't indicate a los...
What does it mean for signals to have impedance? I expect that what it means is that a particular signal source has an effective series resistance (for a voltage source) or, an effective paral...
I want to convert the power from the wall from 208V triple-phase to 208V single-phase before feeding that single-phase into the transformer I got._ Try this using a 1:1, 208 volts isolation tr...
In circuit analysis why always the power has upper hand over energy? One obvious reason: - If we calculate how much power a resistor dissipates we can calculate how hot it will get (knowing i...
a coil with plain on/off functionality, for example a 24VDC relay coil with 700mW max coil power. That means a coil current of 0.7 watts / 24 volts = ~30 mA. A relay might have a coil inducta...
Is the risk of the opamp overdriving the ADC too great for no input protection to be used? I would certainly say yes but, this can usually be easily solved by using a current limit resistor in...
If I connect this to a 12V supply and expose it to 10us pulse: 12V*10us/475uH = 252mA $$$$ This current flows in the primary magnetization inductance (475 μH) after applying 12 volts for 10 μ...
How can I acquire electronic parts/items/modules and ensure that there is minimal risk of them being unsuitable for my project or design?
Apart from the need to match impedances to prevent possibilities of signal reflections and the knock-on issue of signal nulls at your receiver LNA input, an antenna "expects" to be terminated in th...
How do I calculate the inductance and capacitance out from the barrier to make sure it is less than the sensor values? The output capacitance and inductance from your zener barrier is irrelevant ...
A couple of problems stick out; one glaring and one a little subtler. Read this in the data sheet: - You have the enable pin connected to your 25 volt output. I'm not saying this is definitely cau...
I've built a non-inverting op-amp amplifier with a gain of 101 using this circuit: - My input is 10 mV DC and I expected to measure 1.01 volts at the output but I measure 0.81 volts. What has happ...
To avoid shoot-through you should ensure that the active-low P-channel MOSFET gate drive voltage never overlaps with the active-high N-channel MOSFET gate drive voltage. With an inverter driving th...
I'm using a variable duty cycle square-wave oscillator to drive a half-bridge MOSFET pair like this. Upper MOSFET is P-channel type, lower MOSFET is N-channel type: - And, I think I'm getting shoo...
Low-pass impedance transformation Theory Input Impedance: - $$Z_{IN} = j\omega L + \dfrac{\dfrac{R_L}{j\omega C}}{R_L + \dfrac{1}{j\omega C}} = j\omega L +\dfrac{R_L}{1 + j\omega R_L C} = \dfrac{j...
I have a signal at 10 MHz produced from a 50 Ω source. How can I match that to a 300 Ω load with low losses without using an RF transformer (space constraints)? Are there any circuits and formulas ...
I need to design a simple boost converter like this: - I want to control duty cycle from another circuit such as an MCU but, I'm unsure how to proceed. My requirements are: - Input voltage 12 vol...
What is the relationship between the pole zero diagram and bode plot? Case example: a 2nd order RLC low pass filter: - $$\dfrac{V_{OUT}}{V_{IN}} = \dfrac{\frac{1}{j\omega C}}{R+j\omega L +\frac{1}...
I have just raised a Q and A but when editing the answer (that involves a picture) there is no "live" version of the potentially finished post and this will prove to be a problem when making a comp...
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