New answers tagged circuit-design
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what should be the minimum distance between two MOSFETs on same heatsink
Well, should the MOSFETs be thermally coupled? Should they be thermally decoupled? Are they typically losing energy at the same point of time, alternatingly, or uncorrelatedly?
What is your goal? ...
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3
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Can I make a latch using 2 AND gates, instead of NAND gates?
You can make a latch with only one AND gate if you get to cheat:
simulate this circuit – Schematic created using CircuitLab
Reset is dominant when both inputs are high. However, you can't get ...
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0
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Can I make a latch using 2 AND gates, instead of NAND gates?
In theory you could but it completely beats the purpose of why the flip flop is used in the first place. A flip flop is used so it "stores" or "saves" a given binary level (1/0) ...
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Design for LTE - modem, MCU and eSIM - the differences
I'm currently working on an IoT project at work myself as well, so I'm basically going through the same steps you are in trying to architect a unique solution. This is my first time doing an LTE ...
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Pump Auto Shutoff
Independent of the actual motor driver, is there a reason you cannot implement the runtime and cooltime restrictions and logic in Pi firmware?
Circuit #1 certainly is salvageable. The only real ...
- 23.2k
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Pump Auto Shutoff
When using low-power electronics to control anything with a motor in it, I frequently find that it's a lot easier to use a relay instead of a transistor. The on/off transitions are just as sharp as ...
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Chopper Opamp PNoise Simulation
I'm unsure why the curve remains flat even at 1MHz, where flicker noise should be modulated to.
Quite the contrary, a good chopper amplifier must filter out the INPUT flicker noise. In doing this, it ...
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6
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Pump Auto Shutoff
The MCU option is overkill only once; you acquire the programming equipment and software, and you acquire the knowledge to use them, and then you have that for life. In addition, you have a single 8-...
- 47.1k
1
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How to stop undefined behaviour on power loss in an Arduino?
Supplied with 12V AC, the DC output of your rectifier/capacitor arrangement should be about 15V or so. The 5V regulator will begin to drop out when its DC input falls below 8V, so you have plenty of ...
- 47.1k
0
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Linear Regulator Pass Transistor vs Parallel Regulators
I'm not a big fan of paralleling linear regulators for reasons others have noted. I've built variable supplies with LM317/337s using (by)pass transistors, but these are unsatisfying because you have ...
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I am trying to implement a function using only NAND gates
The reason NAND gates are often considered the "most basic" building blocks are that:
They (and NOR) are the least costly in silicon. Four transistors form the core.
The output is more ...
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555 timer sinewave generation
The R1 is 2.2 kΩ which is calculated for ~7.2 kHz
The difference between 7.2kHz and 6.9kHz is negligible - it's all down to component tolerances.
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555 timer sinewave generation
To get a good sine wave, you need to be at the resonant frequency of the LC.
The resonant frequency is:
\$f = \frac{1}{2\pi\sqrt{LC}}\$
I calculate 7.34 kHz for your LC values. Your 555 frequency is ...
- 17.4k
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Lightning Protection for RF (L-Band or higher)
In general usage, we know that GDTs are slower than TVSs. It is necessary to use a TBU (HSP-High Speed Protector) as a buffer element to ensure the GDT operates first and to suppress the residual ...
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3
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Accepted
Multiple electromagnets and limiting current
A 100mA load draws 100mA from a power supply that can provide up to 2A for 20 100mA loads. Basic thing how loads and supplies work. Your computer also draws 100W from mains socket even if there is ...
- 172k
1
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What is the best way to multiplex 64 coils?
The essence of the DGT suggestion
from BitLauncher in comments is that it uses 8 file-wise transmit coils, and 8 rank-wise receive coils, so half of the multiplexing is already done by the geometry of ...
- 174k
1
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Lightning Protection for RF (L-Band or higher)
WRT to the DCB its hard to block DC while passing RF with minimal loss. The broadcast people always liked a shorted quarter wave stub. At FM radio frequencies the losses are essentially zero. Look ...
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0
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Accepted
Polarize and monitor a large resistor like device
this is my 6th iteration on this project...
Get the analog part working on a breadboard first. Not solderless breadboard, but a copper-clad FR4 with glued-down pads for components. QRPme sells those, ...
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Polarize and monitor a large resistor like device
I have LED lighting in my lab that I have to switch off when performing noise measurements, since they radiate horrendous RF. I also have an LCD screen which produces similar crap even when switched ...
- 47.1k
1
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Supplying 12.5 V @ 50 mA at low cost
About ton(max) (I assume the maximum amount of time the circuit will be accumulating before turning off again) -- the datasheet doesn't mention a formula for finding this value. I merely specified the ...
- 1,871
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Accepted
Issue with 2-Digit BCD Adder-Subtractor Circuit Using 74LS83
There are many bugs in your circuit, but there is a particular one that's preventing the "tens" output complementer from operating.
First of all, you should show reference designators for ...
- 178k
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Circuit sanity check: adding 3V LED to 18V Drill Battery
Sanity check
This is not how portable drill ODM's would make a drill LED in volume. They would switch the LED with any trigger and make it efficient and cost reduce it to 10 cents.
You could make a ...
- 148k
2
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PWM logic level shift (filter, signal processor)
The sensor may be illuminated by many different light sources other than the intended one, such as the sun, glare from a window or artificial light flickering at 50/60Hz. If the receiver "sees&...
- 47.1k
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USB-C passthrough (including CC line) not making connection
To summarise and conclude:
It's not possible to create a USB-C pass-through device and remain compliant. To remain compliant, you would have to act as a hub.
The reason it's not possible is that USB-C ...
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2
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PWM logic level shift (filter, signal processor)
The 'bulging' is because the base current tapers off after the pulse rises and the 100nF cap finishes its charging. This by itself shouldn't be an issue for the micro. But, there are other issues.
I ...
- 58.2k
3
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I designed an Op Amp but the feedback loop would not generate the expected behavior
The input stage isn't really differential, you have the collectors connected together when they should be separate.
The simplest way is to have a resistor between each collector and the associated ...
- 27.8k
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Output Capacitor of Buck Converter
\$I_C = I_L - \frac{V_O}{R_L}\$
If \$I_L\$ is greater than the load current (\$\frac{V_O}{R_L}\$) then the capacitor is charged
If \$I_L\$ is less than the load current (\$\frac{V_O}{R_L}\$) then the ...
- 473k
-1
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Output Capacitor of Buck Converter
Everywhere it is treated as if there is a single node equation for period 1 and 2, why ?
I assume you mean that the standard treatment is that there is one set of equations in position 1, and a ...
- 47.1k
1
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Accepted
Buck converter node equation
The current equation is exactly the same for both scenarios i.e. \$I_C = I_L - \frac{V}{R}\$. Or, putting it another way, \$I_L = I_C + \frac{V}{R}\$ (more clearer).
Any part of the equation does ...
- 473k
4
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Pull Down resitor in a npn 2n2222
There's no real need for a pull-down resistor.
The PIC output is push-pull and slightly faster switching is not important in this application.
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Circuit Diagram for powering 32 motors
This is normal to have a start current in DC motors that is >=10x rated current and 12x in highly efficient DC motors. If you compute more than this I'd be suspicious.
The answer is to use current-...
- 148k
0
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Analog long duration timer (5 minutes) using a ramp
This CAN be done with an integrator made with a low bias-current op amp, a rather good 1 microfarad or so capacitor, and a input resistor probably too large to easily find. AND very careful ...
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Photointerrupter with internal pull up Circuit design
Resistance of the internal pull-up on these PIC micros isn't well defined, since it isn't technically a resistor, rather it's implemented by some kind of transistor arrangement exhibiting what looks ...
- 47.1k
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Accepted
Photointerrupter with internal pull up Circuit design
I suggest you turn off the pullup and depend entirely on an external 1% resistor.
With all the variations associated with optocouplers (LED aging, dirt in the gap, temperature changes), who needs an ...
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Calculation of control to output transfer function
The first thing to do, is to run a cycle-by-cycle simulation and verify the converter actually delivers the power. You can use the example from my free ready-made templates, it works on the free demo ...
- 23.5k
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How do the ESP32 and CH340C need to be connected to enable serial communication and auto-reset for boot-loading?
My guess is you switched the BJTs in the original circuit to FETs.
As you see in the FET symbol, it has an internal (intrinsic) diode from Source to Drain, which a BJT does not have.
Which means, when ...
- 172k
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