Problem with Force on rigidbody, not always the same force

Hi, I'm new in the forums, so nice to meet you guys! I'm starting to work in Unity so at the moment I'm watching some tutorials in the net and trying to learn something, at the moment I did a 2D Endless-Run Game for Android wich is a trash hehe.

Well, now im working in a new project, but i have a problem with the script, i have this in the script: enter code hereusing UnityEngine; using System.Collections;

 public class controladorPersonaje : MonoBehaviour {
  
     public float fuerzaSalto = 100f;
  
     public bool enSuelo = true;
     public Transform comprobadorSuelo;
     float comprobadorRadio = 0.07f;
     public LayerMask mascaraSuelo;
     private Animator animator;
  
     void Awake(){
         animator = GetComponent<Animator> ();
         }
  
     // Use this for initialization
     void Start () {
  
     }
  
     void FixedUpdate(){
         enSuelo = Physics2D.OverlapCircle (comprobadorSuelo.position, comprobadorRadio, mascaraSuelo);
         animator.SetBool ("isGrounded", enSuelo);
         }
  
     // Update is called once per frame
  
  
  
  
     void Update () {
         if(enSuelo && Input.GetTouch(0).phase == TouchPhase.Began){
             rigidbody2D.AddForce(new Vector2(0, 200));
         }
     }
  
         }

It allows the character to jump, but the jumps are not ever the same. I mean that the jumps are more highs/low than the others, I tried to change the "Input.touchCount" for Input.GetMouseButtonDown and the jumps are ever the same, but I want that if i hold the touch of the screen the character will be jumping always not for every touch, but with Input.GetMouseButttonDown it doesn't work.

So please if anyone knows a solution i will be very appreciative, because I want to continue with my project as soon is possible, the classrooms come back and I'm bored as hell hehe.

Edit:This code works too (an admin put it):

  if(enSuelo && Input.touchCount == 1 && Input.GetTouch(0).phase == TouchPhase.Began)

but what i want is that if I hold the screen the character will be jumping always with the same jump height.

Thanks and sorry for the long text!