11
votes
Is it good practice to place decoupling capacitors near connector pins?
There is no standard practice.
It depends on the connector and what it is used for.
You put a cap if you need it for some reason, or leave it out if there is no reason to put it.
In some cases it's a ...
- 149k
10
votes
Is it good practice to place decoupling capacitors near connector pins?
People may put them near connectors if there is a possibility of ESD from external wiring damaging the chips on your circuit board. After all, you ideally want the transient to be dealt with at the ...
- 457k
9
votes
Why does my integrator slowly saturate to negative rail in the following configuration?
In a perfectly ideal case, it would.
But the simulator you're using appears to model the op-amp as having nonzero input offset and input bias currents. This means that, as far as the op amp is ...
- 32.6k
6
votes
Is it good practice to place decoupling capacitors near connector pins?
Electrolytics near power inlet connectors can help reduce the overshoot from the interaction of long wire run inductance and low-ESR ceramic converter input caps (see: https://www.analog.com/media/en/...
- 18.4k
5
votes
Accepted
LEDs forward voltage at minimum brightness
The problem with voltage-driving LEDs, which is what you are effectively doing, is that the LED forward voltage varies with temperature. This could explain your anomolous voltage readings, which ...
- 166k
4
votes
Why does my integrator slowly saturate to negative rail in the following configuration?
Why does my integrator slowly saturate to negative rail in the following configuration?
No op-amp is perfect. All op-amps have some offset voltage and bias current. These will eventually saturate an ...
- 23.5k
4
votes
Accepted
Unpowered LM393 Comparators
There is no need to add any circuitry. The inputs can withstand -0.3V to +36V regardless of whether supply voltage is applied or not, and even without current limiting.
Many other comparators (such as ...
- 398k
4
votes
Accepted
How does this debounce circuit (from Arduino Portenta Edge Control) works?
This circuit is not switch de-bouncer. This is actually a pulse generator intended to generate a short pulse based on the IRQ_C_CH2's input low to high transition irrespective of how long that ...
- 3,060
4
votes
VDD and VDDA microcontroller
Some GPIO (KEY#) pins are still connected to the 3V3 rail through resistors (R5, R6, R8). Also the NRST pin is kept connected to the 3V3 rail through R4 resistor.
The GPIOs may have protection (...
- 34.3k
3
votes
Accepted
6 Pin Potentiometer
The reason such 'gang' potentiometers exist is to be able to handle multiple signals with one manual control. Prime example for a 2-gang pot: a stereo volume control.
If you short the two pots ...
- 54.1k
2
votes
Accepted
Why does reducing the load impedance _increase_ the voltage drop, but reducing the source impedance _reduce_ the voltage drop?
The answer will become clear when you realize that the source and load resistance form a 2-resistor voltage divider.
simulate this circuit – Schematic created using CircuitLab
In the first ...
- 21.3k
2
votes
LED indication for driven n-FET inputs
The first schematic will not work as intended. The forward voltage of the LED dominates the gate voltage, so different LED colors will produce different gate voltages and some combinations of LED and ...
- 6,919
2
votes
What is the purpose of the 4 diodes in this circuit?
Let's first give designators to the diodes:
Short answer: Diodes are there to block current to the input in case of a power outage, also they work as "POWER OR" to ensure correct current ...
- 34.3k
2
votes
Accepted
Proteus Simulation Program-Analogue Graph
Your simulation applies 12 volts instantly to an uncharged capacitor thus, dv/dt is theoretically infinite and, the theoretical current into the ideal capacitor is also infinite. The reason why the ...
- 457k
2
votes
6 Pin Potentiometer
That is the equivalent of putting resistors in parallel. Assuming pots are equal, the pot would behave like a pot of half value. The general case is shown here:
simulate this circuit – ...
- 3,060
2
votes
How does this debounce circuit (from Arduino Portenta Edge Control) works?
It's an edge detector. When the input goes high, the output of the AND gate will go high and stay high until C35 charges enough to make the inverter's output go low. The Schmitt trigger is there to ...
- 18.4k
2
votes
Slow simulation speed of a Very High frequency circuit (LTspice)
You are being unrealistic in your expectations for a SPICE simulation. To properly simulate what you show in the schematic involves 600e6 x 20 = 12e9 cycles of the input waveform (600 MHz). The step ...
- 9,619
2
votes
Why does my integrator slowly saturate to negative rail in the following configuration?
Like Hearth and Math said, the opamp has bias current that gets integrated in the long term. Putting a high value resistor across the cap will help. Another trick is to put a resistor in series with ...
- 3,060
2
votes
How does this debounce circuit (from Arduino Portenta Edge Control) works?
If the input is low for a long time for the RC circui to settle, then inverter output is high. So when the actual input goes high, the AND gate goes high, but soon the RC circuit settles and inverter ...
- 149k
2
votes
LEDs forward voltage at minimum brightness
As Neil_UK said in his comment, you can keep the two LEDs in series with no resistor (or a zero ohm jumper instead of a resistor) or 10 ohms, it won't make much difference.
5V is already less than the ...
- 2,330
2
votes
LEDs forward voltage at minimum brightness
You have an MCU -- use your microcontroller as a voltage doubler or tripler. Since you only want to ensure the dimmest illumination, not brightness, this is perfect.
Dave Jones of EEVblog fame has an ...
- 2,820
2
votes
Help designing a manual reset circuit
If your load is tied to 0 volts/GND then it's best to use a high-side switch but, trying to implement this with an N-channel MOSFET is probably more hassle than what it's worth so, instead, use a high-...
- 457k
2
votes
Help designing a manual reset circuit
even if the error signal goes low again
So the error signal's high state is latched. IOW it is setting a flipflop. To reset the flipflop, a Reset button is pushed. However, the Reset function will ...
- 20.1k
2
votes
Can I use an RF transistor at a lower frequency?
Sure, you can! There's nothing wrong with not using a part to its full capabilities.
Note, though, that the internal input matching network of the transistor will be ineffective at such low ...
- 18.8k
2
votes
Can I use an RF transistor at a lower frequency?
One thing you need to be cautious of when using components with gain above your intended operating frequency is the possibility of oscillations or other artifacts at a higher frequency.
For instance, ...
- 10.8k
1
vote
How to increase current by reducing voltage?
The power you specify - 200kW - would serve 10-20 homes, a small apartment complex or a medium-sized light industrial building.
If your power is 400kV AC, you would use a 10:1 step-down transformer to ...
- 54.1k
1
vote
Accepted
Grounding of battery-powered devices
Is this what you meant?
simulate this circuit – Schematic created using CircuitLab
This is fine.
- 35.2k
1
vote
In Altium, how do I create mounting holes for a through hole transistor?
There exits very good tutorials on YouTube or Altium help pages.
Just to name on:
https://m.youtube.com/watch?v=63VKyVByZck
- 51
1
vote
6 Pin Potentiometer
The end-to-end resistance will be approximately half of the individual end-to-end resistances. The combined wiper resistance to an end will be approximately proportional to its position (with any ...
- 18.4k
1
vote
Accepted
12V to 220V modified sine wave inverter simulation
The load was just too high in value and, back-emfs from the flux in the transformer are masking the true power output voltage waveform. From comments: -
Try using a resistor for the load and, not one ...
- 457k
Only top scored, non community-wiki answers of a minimum length are eligible