Should particles be automatically emitted each frame?

	// Emit particles for 3 seconds
	particleEmitter.emit = true;
	yield WaitForSeconds(3);
	// Then stop
	particleEmitter.emit = false;

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    IEnumerator Example() {
        particleEmitter.emit = true;
        yield return new WaitForSeconds(3);
        particleEmitter.emit = false;
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as IEnumerator:
		particleEmitter.emit = true
		yield WaitForSeconds(3)
		particleEmitter.emit = false