【正文】 sembly and debugging cultivation of practical skills, improve the analysis and the ability to solve practical problems. Second, design planning 1, design idea Confuse antitheft telephone controller circuit, if you go out in the outside, as long as you to call home, your house will be issued a voice recorder, dark, indoor light will shine. This circuit by power supply circuit, signal input circuit, trigger circuit, drive circuit and photosensitive sensors, integrated electronic switch circuit posed. 2, design charts Third, each part of the circuit design 1 and power circuit design The direct current voltagestabilized source structure diagram: Utility voltage transformer and pass through the fuse IN4007 diode rectifier, lower blood pressure, LM7805 capactance filtering, avr output, use red leds instructions power circuit work condition and power circuit principle as figure2shows. Figure 2 power circuit 220V utility after transformer T stepdown, output voltage, munication about 9V diode (VD1 ~ VD4) bridge rectifier, capacitance C1 filter out the highfrequency clutter after LM7805 feet, 1 to 2 feet grounding, 3 foot stable output voltage, voltage for 9V. C2 further filter high frequency interference, supply circuit work, red issued diode is the power indicator light emitting diode, R1 is the current limiting resistor, light emitting diode current for normal work of 10mA. Transformer principle is very simple elfevident transformer is main function of variable pressure, also is change voltage. Transformer is principle electromagic induction technology, transformer has two independently of sharing a core of coil. Respectively called transformer subprime coil and primary coil. Current direction and size varies with time, transformer primary tong on ac, transformer core created alternating magic field, (including connect power of winding called primary coil, the rest of the winding called subprime coil. In the same frequency induction subprime is the ac voltage. The first level of transformer winding of turms than equal voltage than. Transformer can only change ac voltage dc voltage, and do not change, because the direct current is not change, current through the transformer won39。t produce alternating magic field, so only in subprime coil directly connected moment produces a instantaneous electric current and voltage. LM7805 is three terminal voltage stabilizer shows: (1) the feet to the input voltage regulator Ui, 3 feet for the grounding end。t reliable direct drive dc relay, reason need to add level 1 transistor amplifier, so the driver output portion posed by the transistor and relays. This circuit relay models 4098, dc resistance to 300 Ω, drive current for 200 ma, reason transistor collector current should be more than 300 ma, set transistor current amplification coefficient for 50, the beta transistor turnon the base current for 300/50 = 6 (ma). Can be calculated resistance R10 = (6V V) / 6mA hundredth 9K Ω, so this circuit Ω R10 take 10 K, triode can be used for 9013, maximum output current 500 milliampere. 5 and photosensitive sensor This circuit photosensitive sensor adopts light activated triode 3DU31, it is one of the most mon photodetector, its sensitive wavelengths in the visible wavelength near infrared wavelength and ultraviolet ray, including wavelength. Light activated triode and ordinary triode similar, also have current amplification e ffect, but it is not just the collector current by passive circuit and current control, but also by ray radiation control. Usually base not derivation, but some light activated triode base have derivations, used for temperature pensation and additional control functions. When having photosensitive properties of PN junction by irradiation, formation, thus resulting in the light of photocurrent born by base into emitter current collector loop, in order to get an enlarged equivalent to beta times the signal current. Different material made of light activated triode have different spectral characteristics and pared with photosensitive diode, has the very big photocurrent amplification, namely high sensitivity. Through to the semiconductor diode and triode learning, I understand the transistor the basic structure and working principle of semiconductor, transistor, is one of the basic ponents, with current amplification effect, is the core of electronic circuit ponents. Transistor is in a semiconductor substrate production two are located very close of PN junction, the two PN junction is divided into three parts, block semiconductor middle part is basebed, two side part is the launch region and integrating electricity area, arrangement have PNP and two NPN transistors, as shown in figure drawn from three areas corresponding electrode, respectively base b emitter e and collector c. Launch region and basebed between PN junction that launch knot, bines electronic zone and basebed between PN junction called the collector. Basebed is very thin, and launch region thicker, impurity, PNP transistor concentration large type emission region fire is the direction of movement, the cavity with current direction, reason emitter to the arrow, NPN transistor launch region firing type is free electrons, which the movement direction and current in opposite directions, so emitter arrow outward. Emitter arrow outward. Emitter arrow in also PN junction in forward voltage under the conduction direction. Silicon transistor and germnium transistor have PNP type and NPN type two kinds. Although key learning transistor amplifying function of transistors, but I more interested in the switch function. Semiconductor like a switch, can pass conduction and the due to control circuit. Semiconductor by adding part of trace element will make its characteristic earthshaking change