Hey everyone, I am Relatively new to diodes. I have been working w/ audio/video for almost 2 years, but now getting my mecp certificite. Anyway.....I am trying to learn all i can on diodes. THe different sizes, etc. I read somewhere that you can line diodes from the battery to cut off the radio at let say 11 volts (so if the car aint running it wont totally drain the battery and just cut the system off). How is that done. I got got basics of diodes, but that is just it. Please help
Never heard of that but I'm sure its possible..I'm not sure if it is possible by using diodes.
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Teamrf wrote:
Never heard of that but I'm sure its possible..I'm not sure if it is possible by using diodes.
Yeah, it'll work, if you remember the .7v drop per diode...
If your deck were to be one that turns off at, say 10V, and your nominal operating voltace is 14.4 volts, but you want the stereo to turn off at 11 volts, thus insuring PLENTY of battery to start the car, you would wire a few diodes in series... the math goes like this:
Terminal voltage of battery = 11.0v
Shut-down voltage of control device = 10.0v
11v-10v=1v total desired drop
If you were to wire two diodes in series, this will give you a 1.4 volt window, and the stereo would turn off closer to 11.4 volts, still safe. One diode would give you a turn off battery voltage of 10.7v, a recoverable level... give the battery 10 minutes, and that much would build back up to start the car just fine...
Diodes are pretty simple to understand, really... they are just one way valves for electricity - current can only flow through them one way. As long as one remembers this, and allows for the forward voltage drop, all will be well...
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."