Time.deltaTime trouble

I’m trying to move a character by holding down the arrow keys, but it’s not working. When I go without Time.deltaTime and just press the arrow keys it works fine. I want to move my character more precisely by holding down the arrow keys.

Help?

This is the code I’m using:

using UnityEngine;

using System.Collections;

public class Ctrl : MonoBehaviour
{
public float speed = 1.5f;

 void Update ()
 {
     if (Input.GetKey(KeyCode.LeftArrow))
     {
         transform.position += Vector3.left * speed * Time.deltaTime;
     }
     if (Input.GetKey(KeyCode.RightArrow))
     {
         transform.position += Vector3.right * speed * Time.deltaTime;
     }
     if (Input.GetKey(KeyCode.UpArrow))
     {
         transform.position += Vector3.up * speed * Time.deltaTime;
     }
     if (Input.GetKey(KeyCode.DownArrow))
     {
         transform.position += Vector3.down * speed * Time.deltaTime;
     }
 }

}

Time.deltaTime isn’t exactly necessary, it just ensures that your character will move an equal amount no matter the frame rate of you program. Because of this, values using Time.deltaTime are generally quite small, so it could just be that you need to greatly increase the speed at which you are moving.