what is inside a fluorescent ballast

{"cid":"91099400","title":"5A 250v Temperature Control Thermal Switch Protector 150 Degrees","imgUrl":"https:\/\/img.chinax.com\/nimg\/1c\/0a\/797780c69ec0764f177a11723000-200x200-1.jpg","attrs":{"Price":"negotiable","Brand Name":"NIDE","Model Number":"NDPJ-RBHQ-62","Minimum Order Quantity":"100000 pcs","Delivery Time":"30 working days","Certification":"CE","Place of Origin":"China","Payment Terms":"L\/C, T\/T","Supply Ability":"10000000 pcs per month","Packaging Details":"Wooden case suitable for sea transportation","Product name":"5A 250v temperature control thermal switch thermal protector","Color":"Natural","Used for":"Industrial water pump motor","Capacity":"5A 250v"}}