4. The VR and packaging of IN4007 and UF4007 are the same, but IN4007 is an ordinary rectifier tube, UF4007 is an efficient rectifier tube, and the low-frequency tube cannot replace the high-frequency tube.

Rectifier diode: a semiconductor device that converts alternating current into DC power. Usually it contains a PN junction with positive and negative terminals. The most important characteristic of diode is unilateral conductivity. In the circuit, the current can only flow in from the anode of the diode and out from the cathode.