Day 23: Experimenting with a relay

Although the L293D is very handy, it has two important constraints: It is limited to 600 mA and it causes the voltage to drop.

The relay below has a 5V 40mA coil. It can deal with a charge up to 1A at 30V. It has the size of a 14-pin IC. Its lower part has a drawing explaining what every pin is for.

Relay_top Relay_bottom

In the following circuit, a 330 Ohms resistor is connected to the common pin, a green LED is connected to the normally closed pin and a red LED is connected to the normally open pin. The power provided is 5V.

Relay_GreenLed Relay_RedLed

As expected, the green LED lights when the coil is turned off and the red LED lights when the coil is energized.

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