The world that the world in reality is electronic technology -- imitate circuit + digital circuit. What walk in imitate circuit is successive signal, be based on time to be all sorts of function of parameter that is to say, and digital circuit is much flatter, with respect to tall n of two kinds of condition or low n (strictly speaking is 3 kinds, still have a kind of mind between n of on any account, condition is sealed) . Learn electronic skill, basically be to carry teaching material + computer emulation software starts work like Multisim+ practice, after having certain academic base, see picture of much analysis principle more, the electrician that teaching material recommends Qin Cenghuang chief editor learns and electronics two teaching material. The graph is simple light accuses to call the police on circuit, with this we are analysed, appreciate wonderful electronic technology. Above all we see circuit is medium R of right bright resistor and dynatron VT1 and VT2, and buzzer HA, so we can guess its job principle probably is the change that is worth because of R block, r block is worth change of two upright voltage to cause dynatron status change, affect the working position of buzzer thereby. Following circuit pictures are built in Multisim emulation software, this is cent of a resistor presses circuit, value of photosensitive resistor block is greater, so its two upright voltage are taller also. Light accuses to call the police the key in circuit yuan parts of an apparatus is dynatron, about the composition of dynatron everybody searchs Qin Cenghuang's teaching material. As a whole no matter be NPN model still be PNP dynatron, collector of B base, C and E blast off extremely 3 cite a base. Resemble speaking of diode couplet thinking of only guide is epicene, speak of dynatron be about to associate " electric current magnifies " , everybody lives dynatron and reality medium faucet analogy (B is valve, c is cistern, e is conduit) understood very easily. It is with NPN dynatron exemple, when voltage is achieved between BE touch hair voltage (0. 7V) when be equivalent to faucet valve opening, right now the water in cistern can flow to conduit, the rate that specific discharge and valve open is concerned, namely dynatron action is magnifying area; Open when valve when rate is the oldest, right now the discharge of the conduit of water flow direction in cistern is fixed, namely dynatron action is in guide an area; There is discharge when valve is shut of course, namely dynatron action is in end area. Return first light to accuse to call the police in circuit, when photosensitive resistor block the value increases some when the value, dynatron VT1 guides (here guide in knowing the working character that is different from dynatron " guide " term, just explain right now dynatron was opened euqally to faucet valve, current has flowed just, the VT2 in later development also is such) , right now flow direction of VT1 collector electric current blasts off extremely, that is to say right now dynatron VT2 base has electric current to had flowed, at the same time generation pressing falls; If dynatron VT2 guides,connect, so buzzer can sound. The principle that builds through Multisim software pursues as follows, adjust when us R3 (photosensitive resistor) when block is worth 40K, the base voltage of dynatron Q2 is 0.
75V, right now buzzer gives out the sound of Di Di. CNC Milling