Hunan Zhuzhou Mo Caojun The analysis of this classmate is not accurate. Before the light is on and after the light is on (no clapping), (1 saturation is turned on, Q2 is off; when the light is on, Q1 is off, (2 is saturated).
The trial analysis is as follows: According to the circuit diagram, set the control circuit power supply = 8V, the transistor C90 丨 3 P = 100, before the light is on, the Q1 base state at this time Q2 will be lower than the base voltage. 5V and cut off, select the triode's |3>73, you can meet the above conclusions, ä¸ clap, MIC conversion. Pulse signal after C1 coupling. Its valley point makes the Q1 base voltage lower than 0.5V, ... cutoff. At this time, after the 1:: light is on, if the clap is stopped, C1 has no signal coupling, and returns to the state where Q1 is saturated and Q2 is off.
The working principle is: after K is turned on at night, the circuit is stable, Q1 is saturated and Q2 is turned off, the voltage of pin 2 of IC1 is greater than 1/3V, :, :, 3 feet output low level; C2 is discharged through 7 feet, so 6 feet Low level, so the output remains low, the circuit is in steady state. When clapping, the microphone MIC converts the sound wave into a variable voltage signal, which is coupled to the base of Q1 through CI. The valley of the signal makes Q1 cut off and Q2 saturates. Pass, so that the voltage of pin 2 of IC1 is less than 1/3V. The foot output is flipped to the level, the 3-pin output trigger current trigger VI is turned on, the bulb DP is illuminated; the 7-pin internal discharge switch is turned off, and the power supply voltage is charged to C2 through R5. After the set delay time, the C2 voltage is greater than 2/3V, x (after the sound stops, Q2 has been cut off), the 3-pin output returns to the steady state, the VI loses the trigger current and blocks, and the bulb goes out; C2 discharge, ready for the next work.
When the collector and the base of a transistor are both at an isoelectric potential of about 0.7 V, the transistor is in a critical saturation state, and the small signal still has amplifying effect, and can still work. The correct answer to this question is also that Zhejiang Dongyang Ma Zhenhong 21 people make electric blankets, stepless thermostat switch, electric heating blankets, generally only two sets of temperature regulation, the voltage of the two ends of the heating wire is 220V when the high temperature is high, and the electric power of the electric wire is supplied by the half-wave rectification when the low temperature is 220V. The blanket stepless thermostat switch can adjust the electric blanket to the most comfortable temperature.
The circuit is shown in the drawing, R,. For 470k with switch potentiometer, ST is a bidirectional trigger diode::, the normal heart switch is in the off state, the bidirectional thyristor BCR is cut off, and the electric blanket is not energized. Rotate R when heating is required. When the switch is closed, the SCR control electrode is triggered by RP, R, and ST, and the AC power supply is turned on to adjust the RP resistance value to change the conduction angle of the SCR, thereby changing the flow through the heating wire. The average current reaches the goal of stepless temperature regulation. R,. The smaller the resistance, the longer the on-time of the SCR, and the higher the average current of the Elecironivs/ill, the higher the temperature.
The temperature regulating switch is simple in manufacture and low in cost, and only needs a few dollars to find an insulating small box, and fixes the RP on the surface of the box for setting the temperature of the electric blanket. Because there are few circuit components, it is not necessary to make a special Printed circuit board, just lap welding directly according to the figure. Fix it, then connect the power cord of the electric blanket to the output end of the insulation box, and finally connect the power plug, and the electric blanket stepless temperature switch is made.
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