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7
votes
1answer
2k views

Why does this rising edge detector using a capacitor and a resistor work?

So in this video from Ben Eater he makes a rising edge detector using a capacitor and a resistor like the one below. simulate this circuit – Schematic created using CircuitLab In the video Ben ...
1
vote
1answer
47 views

RC circuit with pulse input voltage; finding the time constants

I've the following circuit: Question: What are the time constants of the voltage at node \$\text{Y}_2\$ when the up part of the puls comes and when the down part of the puls comes? MY WORK: The ...
0
votes
1answer
186 views

Raspberry Pi hat design

I am designing a Raspberry Pi hat that needs to be able to accept inputs from 3 different water meters. Two of the inputs are 4-20mA signals, the third input being a pulse signal. At the top I have ...
8
votes
4answers
809 views

Pulse withstanding capability of standard resistors

How much pulse power does a standard (i. e. not further specified) resistor withstand? Consider for example a MOSFET and a 33R resistor that is connected to its gate. If the switching voltage would ...
-2
votes
3answers
2k views

how to make a 0.5w resistor from 0.25w resistors [duplicate]

Can I use two or more of 0.25 W resistors to get a 0.5 W resistor? How do I make a 220Ω 0.5 W resistor using 0.25 W resistors (no matter what the value of the resistors). All I know is V=I×RV=I×R (...
1
vote
0answers
428 views

Pulse sensor: Choosing the right resistor for the phototransistor

I want to use specifically the SFH 309 NPN phototransistor in order to create a pulse sensor that works as seen below: The IR diode emits IR light to the fingertip from the one side and on the other ...
2
votes
1answer
2k views

One shot pulse Push Button

How could I make a circuit where whenever a push button is pressed, the output would be a single pulse ? The pulses duration has to always be the same regardless of how long the button is held down. ...
4
votes
2answers
4k views

Resistor power rating for short pulses

Just wondering how to treat a resistor power rating if the resistor is only getting current passed through it for 1us or less? Is it reasonable to exceed the power rating significantly (say 10x) for ...
6
votes
1answer
1k views

Automotive circuit works but with lots of heat. Is there a better way?

The Problem I have a vehicle that is ‘smart’ enough to detect when a trailer is attached. When a trailer is attached it changes ABS and vehicle stability control parameters, turns off the reversing ...