5 mA, 50mV, 10 ohms, could be used in a 1A circuit?

Question

can someone show me the formulae and working out used plz

does anyone know how to draw a diagram including component values

cheers

Answer 1

Any device can be used in a circuit, if you know what you're doing.

A series circuit has all the devices in a single line (which means the same current runs through them all, and the total of their voltage drops is the circuit drop). A parallel circuit has some (or all) the devices in separate paths (which means each path has it's own current which, when added together, total the circuit current ... and each path has the same voltage drop as the other paths.

A resistor is defined by several things; one of these is the actual RESISTANCE. Another is the POWER DISSIPATION, which basically equates to its ability to get rid of heat.

Ohm's Law is pretty basic:
(Voltage in volts) = (Current in amperes) * (Resistance in ohms)
0.050 = 0.005 * 10

Power dissipation, for the same resistor, is
(Power in watts) = (Current in amperes) * (voltage in volts)
P = 0.005 * 0.050 = 0.00025

To use this device in a 1 amp circuit means there has to be another branch that will handle a significant (1-0.005 amperes) portion of the "circuit current". For comparison purposes, this would mean another resistor rated 0.05025 ohms, 1 amp, 0.05 volt.

To simply "plug in" your resistor as a series element in a 1 amp circuit would burn it out - it simply cannot dissipate the heat generated by that amount of current.

Answer 2

voltage in volts = current in amps * resistance in ohms

Your problem:
0.050 volts = 0.005 amps * 10 ohms
is correct. This is a voltage source with a resistor across its terminals.

You could use a 10 ohm resistor in a 1.0 amp circuit if it were rated for higher power.
Power in watts = current in amps * current in amps * resistance in ohms
In that circuit, the resistor would need to be rated at least:
Power in watts = 1 * 1 * 10 = 10 watts

Hope this helps!

Answer 3

No; a 5 mA rated component cannot handle 1 ampere!