# resistor

1. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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. ### 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...
8. ### 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. ### 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...