4
votes
Accepted
Name of this 4-pin fan connector?
They are both: single-wall wire-to-board connectors. But ...
Top: CPU fan connector female plug. 2.54 mm pitch, unlatched, compatible with 3 and 4-circuit PCB headers. (my site)
Bottom: JST VH male ...
- 18.9k
3
votes
How to filter a noisy PWM signal without affecting rise and fall times
What filter would you recommended to clean this signal without affecting the rise and fall times
Mathematically, it's impossible to do this with a linear filter, as a sharp edge has an infinite ...
- 90.9k
3
votes
Accepted
How to create a PWM source with fixed frequency and decreasing duty cycle (at some interval) in LTspice?
Probably brute-forcing a solution using a PWL source is the quickest way to a solution. It's very useful for weird and/or complex sources. Once you dabble in generating your own PWLs using a ...
- 3,975
3
votes
How to create a PWM source with fixed frequency and decreasing duty cycle (at some interval) in LTspice?
For an arbitrary stimulus in SPICE I write a program in some other language (I like AWK, you might prefer something else like Python) that writes an output file containing the definition of a PWL ...
- 2,665
2
votes
A simple solution to the PWM controlled DC fan?
No, and no. The DC dimmer assumes a non-reactive load (LED) so it won't behave well with a fan. And, it has a max voltage of 24V which exceeds the fan spec input voltage (12V), and probably frying it ...
- 51.2k
2
votes
Accepted
How to filter a noisy PWM signal without affecting rise and fall times
You should be able to filter out the high frequency component fairly easily, since it's an order of magnitude higher than your signal of interest.
Your signal is 88Hz, maybe up a couple hundred if you ...
- 6,635
1
vote
Scaling PWM amplitude using analog switch at MHz timescales
The ringing you see at both rising and falling edges is caused by the switch or by the traces/cables.
But any problem that you see after a rising edge, but not after a falling edge, is caused by the ...
- 18.9k
1
vote
I2C slave PWM Verilog problems
The problem is in the testbench code. You did not drive the SCL input. Change:
.SCL(SCL),
to:
...
- 6,980
1
vote
How can I implement current control for proportional valves?
The 16-mm valve recommended PWM frequency is 1000 Hz; the 22-mm valve is 500 Hz.
Your circuit has just a few issues: An LM358 performs poorly going in and out of saturation, and even with an "...
- 10.6k
1
vote
Convert square wave to DC using opamps
If the PWM circuit has an asymmetrical output impedance that is significant with respect to the 12kΩ resistor then you'll get an 'offset'.
For example, if the PWM cicuit is a BJT with a pullup ...
- 385k
1
vote
How do I set a 4-channel PWM with I2C in Verilog?
When I compile your Verilog code with the Synopsys VCS simulator, I get a warning message:
...
- 6,980
1
vote
Can PWM be stacked?
Just put an R-C filter after each PWM output. That will convert the PWM back to analog, and thus avoid problems such as negative spikes.
- 1,791
1
vote
Building a constant current circuit
The best circuit for a fine-tunable constant current source would be a Howland Current Pump. There are various versions of it, and the version I prefer using in particular is the following:
Image ...
- 326
1
vote
How to create a PWM source with fixed frequency and decreasing duty cycle (at some interval) in LTspice?
I'm not exactly sure what you want to do, but I might have a way to accomplish it that is unproven.
Look at the models for the LTC6993 (there are several with different features. They can do many ...
- 78.1k
1
vote
How to filter a noisy PWM signal without affecting rise and fall times
What filter would you recommended to clean this signal without affecting the rise and fall times of the PWM (such as a LPF would do)?
Do you simply need to measure the frequency and duty ratio of the ...
- 20.8k
1
vote
Is keeping average current low a way to avoid damage to PSU and MOSFETs?
PWM is a process in which we reduce the total power by reducing the percentage of time power is supplied. In order for it to work well, there needs to be something to smooth the power out. Things like ...
- 2,090
1
vote
Motor Driver Project using 555 Timer PWM + 4N25 + 2N7000
Power source: two 12V dc, 450mA power supplies
Oh, that's interesting! It means your supply is inherently supplying less current than your motor might be able to sink.
This is relevant in this ...
- 90.9k
1
vote
Duty cycle in Sine PWM and Conduction Losses in a MOSFET
Simply skip this Eq. (1) with its arcane definition of 'duty cycle', as this D(α) never appears further on, and you can proceed to where the equation (9) is derived.
First, the authors introduce the ...
- 3,904
1
vote
Is it possible to modify 8-pin Christmas tree LED controller's functions?
Realistically, your only option is:
Reverse engineer the whole board.
Work out what microcontroller they have used from the pinout. There may be several common ones that would be compatible.
Buy a ...
- 19k
Only top scored, non community-wiki answers of a minimum length are eligible