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Beginner question regarding battery charge and circuits

alphaai

May 24, 2011
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Hello,

I am newbie here who has some questions. Hoping someone could help explain why to me.

1) Electronic components draw battery charge from a battery only when component is connected in a circuit to that battery. What happens if the component receives too much current? will it blow and will that cause a break in the circuit?

2) So lets say I had three circuits, A, B, C and I wanted to see how I could best maintain battery charge without blowing up electronic components that are located in circuit C and without increasing loss of power via adding resistors, could I build a circuit where I tell the circuit, "ok I would like current to flow down circuit A","I also would like current to flow down circuit B" (if I decide to), and "I would like current to flow down to circuit C". How is that achieved?

Thanks,

Ben
 
Last edited:

Colin Mitchell

Aug 31, 2014
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"electronic components that are located in Area C "
You only have to be careful of components located in area 51
 

chopnhack

Apr 28, 2014
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Diodes could serve the purpose to some extent as they act as one way valves for flow, switches and transistors for that matter too. There is a slight loss across the diode - certainly not the most efficient way to reduce power. Can you elaborate more on what you want to accomplish and what parts you are working with?
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
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Hi Ben and welcome to Electronics Point :)
Electronic components draw battery charge from a battery only when component is connected in a circuit to that battery.
Right. The battery produces a voltage ("potential difference") between its terminals, and if an external circuit is connected to both terminals, current will flow from the positive battery terminal, through the circuit, and back to the battery negative terminal. (This description is for "conventional" current, which flows from positive to negative, and is the usual model used in electronics.)
What happens if the component receives too much current? will it blow and will that cause a break in the circuit?
It depends on the component. A light bulb or a fuse will overheat and blow, in a way that you can see with the naked eye, and when this happens, the path for current is broken and no current can flow.

If too much current flows through a resistor, as the current is increased it will get hot, then it will smoke, then glow red, then possibly catch fire, then glow incandescent, then usually, it will fail open circuit and/or fall apart, I think.

If too much current flows through a semiconductor, such as a diode or a transistor, it can fail extremely quickly. When that happens, generally the semiconductor goes short circuit. This can cause an even higher current to flow, and that may cause other semiconductors in the circuit to fail.
2) So lets say I had three circuits, A, B, C and I wanted to see how I could best maintain battery charge without blowing up electronic components that are located in circuit C and without increasing loss of power via adding resistors, could I build a circuit where I tell the circuit, "ok I would like current to flow down circuit A","I also would like current to flow down circuit B" (if I decide to), and "I would like current to flow down to circuit C". How is that achieved?
You can switch currents with switches, obviously, but these require mechanical action. Automatic switching can be done with relays, which are mechanical switches that are controlled by a voltage that's applied across the coil. This causes the coil to become an electromagnet, and that pulls the contacts together.

There are also solid state relays, which behave like relays but have no moving parts so they don't wear out with each operation, and various semiconductors can also be used to switch current paths. Commonly, SCRs and triacs are used for switching AC mains voltages, and bipolar junction transistors (BJTs, also known as just "transistors"), and MOSFETs, are used for switching DC. Generally.

If you have some specific application or project, tell us what you want to do and we can suggest what kind of switching device to use.
 
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