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mearvk
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I have a 12 volt transformer (120v in) that I'm trying to use with low current devices (LM386 amp). My question is when I use my meter to read amperage or voltage I'm fully loading the circuit so I get like 2 amps across my resistors and capacitors. I don't need anywhere near this amount, instead I want maybe .350 amps. Currently I'm using a full-bridge rectifier.
So a couple questions:
If I put this DC system into a circuit that 'draws' .350 amps (the LM386) will it still try to 'push' the 2 amps? Presumably not, which leads me to the next question.
If I'm building a circuit piece by piece (adding resistors etc as I go) how can I test what the amperage/voltage will be if my multimeter is always checking under the assumption of 'full load', which it seems to be doing? This would pull ~2 amps which would fry the circuit components in this case.
Finally, sort of unrelated, capacitors have a negative band on the side. I'm unsure if this means the negative side faces towards ground or if the negative side indicates voltage going towards ground (from Vs+ to Vs-). I have seen it work, strangely, both ways. My LM386's capacitor is facing one way but on my breadboard I only get current if I face it the other way.
Option A: Vs+ [- +] Vs-
Option B: Vs+ [+ -] Vs-
The [- +] is the capacitor. Let's put this baby to bed. Which is it?
So a couple questions:
If I put this DC system into a circuit that 'draws' .350 amps (the LM386) will it still try to 'push' the 2 amps? Presumably not, which leads me to the next question.
If I'm building a circuit piece by piece (adding resistors etc as I go) how can I test what the amperage/voltage will be if my multimeter is always checking under the assumption of 'full load', which it seems to be doing? This would pull ~2 amps which would fry the circuit components in this case.
Finally, sort of unrelated, capacitors have a negative band on the side. I'm unsure if this means the negative side faces towards ground or if the negative side indicates voltage going towards ground (from Vs+ to Vs-). I have seen it work, strangely, both ways. My LM386's capacitor is facing one way but on my breadboard I only get current if I face it the other way.
Option A: Vs+ [- +] Vs-
Option B: Vs+ [+ -] Vs-
The [- +] is the capacitor. Let's put this baby to bed. Which is it?
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