You have acquired a transceiver and connected it to a power supply. When you switch on the power supply, its fuse blows immediately. What circuit malfunction caused the fuse to blow?

A fuse is a safety device designed to sacrifice itself by melting (blowing) when dangerously high current flows through it. This breaks the connection and protects the rest of the equipment from catching fire or sustaining severe damage. A 'short circuit' occurs when current finds an unintended, incredibly low-resistance path that bypasses the normal electrical load. According to Ohm's Law, when resistance drops to near zero, current spikes to massive levels. This sudden surge immediately exceeds the fuse's current rating, causing it to blow. An 'open circuit,' on the other hand, means the path is broken and zero current flows, which would never blow a fuse.