Posts by Andy aka
What would be the main considerations to use Pi-filters for EMC? Using the filter correctly and understanding its limitations EMC or EMI (electromagnetic interference) is noted for its high frequ...
If you search through the electrolytic capacitor offerings from distributors like Farnell, RS, Digikey or Mouser, you find that the maximum life-time rating is commonly quoted as 5,000 or 10,000 ho...
What benefit has a differential amplifier when measuring the signal from a sensor that is remotely located such as in this example: - Why can't I use an arrangement like this: -
What are the advantages of such DC offset removal loop, compared to an RC high-pass filter? The primary advantage is that it keeps the front-end amplifier output centred in its DC operating re...
To understand why complementary pairs are used, it's probably a good idea to think about the limitations of the NPN emitter-follower circuit: - It's a good circuit for delivering modest powers to ...
The magnetic field will always be strongest in the middle of the solenoid. It will be slightly less at the ends of the solenoid and, it will be a lower value on the outside of the coil half way bet...
For any 2nd order low pass filter, the components (R, L and C for electrical and k, M and c for mechanical) can be reduced into two more meaningful quantities: - $\zeta$ (the damping ratio) $\omeg...
What kind of IC can be used to drive the MOSFET, so that when the voltage drops below 6.2 V the battery disconnects from the load? That reverse protection MOSFET works fine for reverse protect...
Most of the energy produced by the CT windings is being wasted in the internal burden resistor. See this data sheet to see what I mean. I calculate that it has a 60 Ω burden resistor and, at full p...
You might get lucky and be able to measure the input resistance using this method. It should work because the black socket (common) is shared by all measurements.
Which topology is preferable? The one below because the LED driver is less likely to produce instability and, if it does, you can always tweak C4 (upwards) in order to kill-off the potentially...
What part of the absolute maximum ratings for the A and B data lines do you think would be protected by 33 volt TVS diodes: - If the chip is powered from a 5 volt supply then you use 5.6 volt TV...
It's got nothing to do with the MOSFET's miller capacitance. Miller capacitance causes problems in common-source circuits but, your circuit is common-drain (or source follower) hence, with a steady...
A loss-less coaxial cable has inductance and capacitance and, their associated formulas introduce $\epsilon$ and $\mu$. But, to home-in on the velocity of propagation, the characteristic impedance ...
The website that I mentioned before mentions the max flux density in ferrites at 400 kHz as being close to 0.04 T. Is this correct? No, you have misinterpreted the graph. The graph shown is fl...
The Murata part you have chosen as a replacement is unsuitable. Its only application is to cheaply replace crystals in oscillators and, as such, it will have a profoundly tight bandwidth (maybe les...
The data sheet gives a perfectly good example of using the nRF24L01 without an external PA. It has an internal PA capable of driving an antenna <-- just look at the design example on page 63 wit...
How can we extract a DC signal from a mixed signal? You use a low-pass filter with a cut-off frequency that is significantly lower than your lowest AC signal frequency. If you need better filt...
Why has my reputation dropped significantly over-night from around 352 to 316? Why are there a bunch of new people listed with decent reputations who seem to have appeared from nowhere?
General cause of noise/interference The interference can be distant (such as lightning) or much closer (such as cables connecting "other" equipment) but, whatever the source, interference can be re...
Input offset voltage $V_{OS}$ Your problem might be input offset voltage or $V_{OS}$. This can be several milli-volts and manifests as this modification to your original circuit (in red): - So, fo...
I'm adding to Olin's answer with a little bit of theory (from the standpoint of an EE) and I'm also showing a 2nd order IIR filter. The 2nd order filter is based on cascading two 1st order stages w...
An on-line boost converter calculator Image from this website. The Operating Mode The circuit operates in either of two modes but, the voltage transfer equation is different for each mode. Therefo...
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...
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...
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