摘要 |
To the common point (C) of two transistors of a magnetron, switched converter power circuit is connected a coupling capacitor which provides input to a starter circuit. A transistor switch id in series with a capacitor and a diode. When the switch is off no current flows in (D11). When the switch is made, (D11) conducts during alternate halves of cycles present a (C). A second diode also conducts and allows current to pass through discharge capacitor. This progressively charges until the voltage across it reaches the breakdown voltage of a gas discharge tube (GTD). Whereupon the capacitor discharges through the primary winding of transformer (TR2). The second winding has many more turns and a started voltage is induced in the starter electrode. This is isolated from the Faraday cage and terminates adjacent to the crucible, close to the void. |