晶体管已广泛应用于社会生产及日常生活的各个领域,各种简单实用的晶体管电路及小产品越来越多。下面介绍几种简单的三极管应用电路,供读者参考。 电子门铃 图1(a)是一种最简单的电子门铃电路,它能发出单音调的音响,可供一般家庭和旅店使用。 在图1(a)中,三极管T1、T2组成高增益放大器,T1集电极与T2基极相连,T1集电极电流作为T2基极电流,T2饱和导通,使T2有较大的输出电流。电阻R2和电容C组成正反馈电路,使电路产生振荡。R1是放大器T1的基极偏流电阻,提供基极电流。当合上开关SB后,电源通过R1给T1提供偏流,使T1产生集电极电流,从而T2 Transistors have been widely used in various fields of social production and daily life, and various simple and practical transistor circuits and small products are more and more used. Here are a few simple transistor application circuit for readers reference. Figure 1 (a) is the simplest electronic doorbell circuit that emits monophonic sound for use in the average home and in the hotel. In Figure 1 (a), the transistor T1, T2 form a high-gain amplifier, T1 collector connected to the base T2, T1 collector current as the T2 base current, T2 saturation conduction, so that T2 has a larger output current. Resistor R2 and capacitor C constitute a positive feedback circuit, the circuit oscillation. R1 is the base bias resistor of amplifier T1, which provides the base current. When the switch SB is closed, the power supply provides bias current to T1 through R1, so that a collector current is generated at T1, so that T2