I got a 2nd hand pressure cooker and yesterday I used it for the first time. It scared the hell out of me!

I've used a pressure cooker before at my parent's place and theirs makes this continuous whistle after ramping up. It's the jiggle-top kind of cooker, like mine. However, mine only makes a subtle hiss and then releases steam as if a gate to hell opens inside. See here: https://photos.app.goo.gl/B7qkGWx7huqbujS48 . Why on earth does it not start jiggling ?

Is my pressure cooker broken ? Or is it due to the electric hob, which instead of giving heat continuously, it switches on and off at regular intervals. When I lowered the heat, it still made steam instead of jiggling, but at longer intervals.

Thanks all!