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例1 香港产U—203型收录音钟控电子电话机无振铃声故障。该机是香港生产的电子电话机。由于该机没有电路图,笔者依照实物测绘出了其振铃部分电路(如图1所示)。该机的振铃电路是以三极管T为主要元件接成的间歇式振荡电路。当线路上来的铃流电压,经C1耦合,R1降压、D2稳压后,供振荡电路工作,并带动B2
Example 1 Hong Kong produced U-203-type recording clock electronic telephone without ringing sound failure. This machine is produced in Hong Kong electronic phone. Because there is no circuit diagram of the machine, the author in accordance with the physical mapping of the ring part of the circuit (as shown in Figure 1). The machine ringing circuit is the transistor T as the main components connected to the intermittent oscillation circuit. When the line up the bell flow voltage, the C1 coupling, R1 step-down, D2 regulator for oscillation circuit, and drive B2