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  1. C

    What frequency value to use to find the correct time constant for a 22kΩ resistor?

    Hey guys, I have just been introduced to time constants and I'm having some trouble with this question. What frequency value do you plan to use to obtain the correct time constant for a 22 kΩ resistor? (Hint: It takes five time constants for a capacitor to go through the full charging...
  2. F

    Resistor Parasitic Capacitance and RF Operating point

    As a reference to my question; I know that a 10K ohm resistor that has a parasitic capacitance of .3pF at 200MHz will have a actual impedance value of 2.564K ohms. If this resistor is used in a bias network for an RF amplifier, how does this shift in resistance effect the RF operating point...
  3. T

    How to calculate value of a Resistor for a Circuit ?

    Simple LED circuit doubt. Assume : I have a LED with forward voltage of 3.0 V and forward Current of 350mA. With 9V battery, i would be calculating the required Resistance with the Ohms law : R = ( Source Voltage - Forward Voltage) / Forward Current. Here we dont consider the Current Ouput...
  4. S

    Help!!!!!, Relay in motorcycle 12V environment,

    Hello, I was hoping some can help me figure if i can use SRD-12VDC-SL-C, to turn may parking light into blinkers. Here is the issue; I purchased aftermarket blinkers for my motorcycle, these only light up while blinkers are turn on, making you less visible during regular operation. Hence...
  5. MhTechDev

    Resistor Scanner App

    Hej all, even though this is not really a electronics project in itself, it might be useful for many of you. After spending a lot of time decoding resistors and still don´t knowing the color code table by heart, I chose to write an app to detect the resistors for me. I am new to Android...
  6. K

    Needing simple solution to get a toy steam engine dynamo to power a USB port

    I will admit from the git-go that i am almost totally electronically illiterate. So please factor that into any responce. Here is what i am trying to accomplish. I would like to use a toy steam engine dynamo to power a USB port for the purpose of charging phones etc. Here is a link to a...
  7. Matienzo

    Heated 35x50 mm surface.

    Hi there, I'm trying to create an electric heater for an insect repellent mat. The only constraint is that I must use a 18650 battery. The mats are about 35x50 mm and they need to be heated at about 130F. In the chat, Mike_2545 suggested a power resistor like this one and also pointed...

    Failed deWalt battery charger

    Got this charger given to me if it was worth repairing. I found both transistors shorted to zero ohms across all terminals and the resistor blown open circuit. See the hole in the yellow band. Don't know what caused it but I reckon it is a throwaway.
  9. G

    LTspice Thin Film Resistor Simulation

    Alright, my question is pretty simple to ask but perhaps rather difficult to solve. I am modelling in LTspice a channel of previous design and analysing various noise figure across the channel. Currently I am using the stock resistors supplied in LTspice. I was wondering if there is a way to...

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