Adjusting the operating point is to adjust the collector current. Collector current at native levels are:
IA=0.3~0.6 Ma, IB=1.1~1.5 Ma, IC=3.5~5.0 Ma, ID=0.5~1 Ma (reference value, transistor β is different, the current will vary). Total current of about 15 Ma.
When you adjust the collector current, ammeter into the circuit's position, where x in the diagram. Adjust the bias resistors of components at all levels. It is worth mentioning that, as long as the transistors and other components to meet the requirements and welding right, collector currents, can meet the requirements without adjustment. When adjusting the operating point, generally starting from the amplifier, by the back-forward-level debugging. Working point adjustment at all levels has been completed, adjust double capacitor can receive the broadcast.