Radar Basics

Mode of operation of the charging coil

1. In the initial state, the circuit is de-energized. This is symbolized by the open switch.
    
2. The voltage is switched on. A charging current begins to flow. The charging coil acts as an inductive resistor against the current. A strong magnetic field arises in the charging coil.
    
3. When the capacitor is almost fully charged, the charging current decreases. The magnetic field in the choke collapses and induces a voltage in the charging coil. This induced voltage is opposite to the voltage applied when the magnetic field was created.
   The charging coil thus acts as an additional voltage source in series to the voltage still present from the power supply block.
    
4. The capacitor is now charged to a maximum of twice the voltage of the power supply block. The magnetic field has completely collapsed. No charging current flows any more. The charging diode prevents the capacitors of the pulse forming network from discharging via the internal resistance of the power supply block.