All Questions
21
questions
1
vote
1
answer
225
views
What is a suitable resistor value for this circuit?
See the small circuit of a PIR motion sensor below. I've tried to find more than one circuit online but every single time it shows a different value for the resistor.
I would be grateful if anyone can ...
- 11
-1
votes
1
answer
239
views
Why is this 2 pin 12V mechanical flasher relay on continuously instead of flashing?
+12V is connected to the B terminal, and one end of a regular bulb is connected to the L terminal, and other end of the bulb is grounded, butthe bulb does not blink at all. It is continuously on.
What ...
- 63
2
votes
2
answers
600
views
LED with built-in resistor and voltage drop
I accidentally bought 12 V LEDs, so an LED with a built-in resistor (you can see it as a black dot on the anode).
Now I measured the voltage and get after the LED still a voltage of 11.3 V, when the ...
- 129
0
votes
1
answer
2k
views
Value of resistor to limit current to 1 ampere in 12 volts circuit
I want to connect my modem directly to a 12volt battery so that I dont need a adapter. My modem’s specs says that it need 12 volt 1 ampere as input.Now the voltage of 12 volts can be directly given by ...
- 39
0
votes
2
answers
648
views
Raspberry Pi Zero 12V Battery backup to 5V - do I need the resistor?
I found this diagram on the internet which seems to divide the voltage down to 5V and still be able to deliver 1A with the 7805 just like I want.
It will use a 12V lead acid battery and a 12V IN ...
- 13
0
votes
1
answer
153
views
Check for 12V with Arduino (Two resistors and a diode)
I need to read the presence of 12V on one of the lines of the board. I want to read using Arduino UNO.
I found the following scheme:
Is this scheme correct?
- 535
0
votes
3
answers
237
views
Calculating the resistance needed
I am trying to calculate the resistance and power Rating for a resistor. I have a 12V 2A power supply and I'm trying to divide it across different motors that are rated for 12V at 0.32A. I understand ...
- 1
0
votes
1
answer
854
views
10 W LED COB on 12 V
So say I have a 10 W LED, most have a forward voltage of 9-11 V and a maximum current of 700 mA.
If I wanted to connect it up to 13 V (a fully charged SLA battery) couldn't I simply do 11-13=2 (LED ...
1
vote
1
answer
1k
views
Powering thermoelectric cooler and fans with 12V input
I was considering a project with a thermoelectric cooling module rated 60w and so obtained an AC power supply of output DC 12V and 4.16A. I'm very new to electronics so excuse me for the basic ...
- 13
2
votes
2
answers
6k
views
Motorcycle turn lights switch to led
So I have this modification to my electrical system on a motorcycle. The voltage on my motorcycle is 12V and I switched from classic lights to led light (both front and rear). My problem (which I ...
- 23
1
vote
5
answers
1k
views
Quick Question about ohms law and resistors
This may have been asked before, but I'm currently I'm an argument about whether or not passing 12v through a .1 ohm resistor would result in 120 amps due to Ohm's Law. (I=V/R)
Providing that the ...
-7
votes
1
answer
18k
views
How much resistance to drop voltage from 18 v to 12 v dc? [closed]
I am going to make a electronic model for my project. I need to drop voltage from 18 v to 12 v for running a 12v dc motor.
So how much resistor i need?
May i use leds in series to drop voltage ? ...
1
vote
4
answers
879
views
Reverse Polarity
I am working on a project and I want to use a \$12\textrm{ V}\$ linear actuator which travels in and out by reversing polarity on the 2 lead conductors. I also have a double pole double throw switch ...
- 11
1
vote
1
answer
1k
views
How to wire multiple 2 volt flickering LEDs to work on 12V auto system
I have tried to use the site to find an answer to this, but it seems everyone that has asked questions have different variables than I am dealing with, and I can't ever seem to grasp electrical ...
- 11
1
vote
3
answers
320
views
Messing with rgb leds and have a question
I have some LEDs that I'm wanting to use in a project. I would like to know what's the best resistor I would need to get the most light out of the 3 different colors using a 12v source. I've measured ...
- 131