why do people never connect the diode directly to a power supply? what would happened if we did this?

Answer 1

The most likely result would be burning out the diode. Diodes are designed to work with very small currents and voltages, most power supplies are too large for the diode to handle directly.

Hope this helps,
Lorax

Answer 2

Diode is generally connected to the power supply through a transformer.We cannot connect the diode to the power supply directly because:-
1.Direct connection to the power supply increases the risk of shock.
2.The forward current or reverse current flowing through a diode has a maximum limit.The diode will be damaged if this limit is crossed(due to excessive heating).The step up or step down transformer allows us to increase or decrease the voltage so that it remains within the maximum limit.

Answer 3

Because the whole power would flow through the diode. In any case you would never connect an ordinary diode in this way as that would be pointless. Unless it was a light emitting diode but you forgot to mention that.

An LED can only take a small current, typically 20 to 40mA so you need some way of limiting the current. A resistor is a good way to do this.

Answer 4

Diodes have a preferred direction. If you apply a voltage in the "backwards" direction, the diode strongly opposes the voltage, and no current flows.

However, if you apply the voltage in the "forwards" direction, the diode offers almost zero resistance, and a very large current will flow. This large current heats up the diode so rapidly that it will literally explode.

Answer 5

sometimes it's done

putting a series diode directly onto a power-supply
will prevent reverse-polarity connection(s) with some circuitry

Answer 6

the poor diode would burn out