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I know you say an incandescent test light will not damage an ECM or PCM, but what do you say to this video? I am confused.
Which test lights are computer safe? Measurements and fried electronics reveal the answer!
Where exactly do you see Paul endorse to use a test light erroneously as shown in the video? Knowing your tools and their limitations is a recurrent theme in Paul's teaching.
Jerry "G" Truglia never got tired to point out that surpassing 1200 mA for more than 6ms potentially is a death sentence for pcm drivers. The example video does not respect these limits. In the end destruction of a component will take place even with a led test light once it pushes the circuit beyond the limit.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
First thing that comes to mind is the current rating of the transistor used in the demonstration. Is it rated for steady 1.11A draw? :huh: To my mind, if the additional 200mA was what cooked that transistor, then the transistor might have been overloaded already...
Like Juergen said, knowing the circuit you're working on AND the characteristics of your tools are key. As long as the tool you're using isn't overloading the circuit, you're fine.
LED testers get tagged as 'safe' because they don't draw enough to harm anything. But they also won't expose the kind of circuit problems that happen all the time in cars/trucks. A place I worked at previously flat out BANNED LED test lights in their shop. Why? Because of how many parts got replaced over a voltage drop problem that an LED test light missed.
Hello Sir,
Thank you for your reply. "Where exactly do you see Paul endorse to use a test light erroneously as shown in the video?"
Can you explain where the error is in the video?
I also see other people state that an incandescent test light is a "dead short" until the incandescent bulb heats up and has resistance, and some people suggest putting a resistor in series with the test light. What are your thoughts on this?
The error consists in putting the circuit under an overload condition.
Though the resistance of the test light bulb is significantly lower during the first miliseconds - while still cold - when switching on the circuit it is NOT a "dead short". The cold filament has some resistance and hence it is limiting the current flow in the circuit. Wether this is a potential danger for a specific component or not will depend on the component characteristics and specs.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
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