Circuit Training: Am I doing this right?

nana_pancakes

So I've been trying to add more weights and strength exercises to my normal cardio routine and so after about 30 mins of running/incline walking I'll do 4 sets of 3 or 4 different exercises, usually 30 reps each. I don't think I'm moving slowly through them, but it'll usually add on another 30/40 minutes to my workout.
But then when I look online for circuit ideas there's usually twice the amount of exercises listed, so I feel like I'm doing it wrong. Am I still going to see results from just doing 3 or 4 exercises a bunch of times or do I need more variation and less sets?

Yi5hedr3

Always pumps Iron first, followed by cardio if you wish.

lorrpb

I take a circuit class on Sat. We usually have 6-7 stations /exercises. We do each station for 60-90 seconds. Some exercises are changed in the 2nd round. We do 2 circuits/rounds, thorough warm up to start, stretching at end. I think the format is pretty flexible but if you are spending 30-40 min I would say do more than 3 exercises. There are lots of muscle groups you can target with diff exercises.