Memory chip

Oscillator (English: oscillator) is an energy conversion device that converts DC power into AC power with a certain frequency. The circuit that constitutes it is called an oscillator circuit.
The oscillator can be mainly divided into two types: a harmonic oscillator and a relaxation oscillator. It can convert DC power into an electronic circuit or device with a certain frequency of AC signal output. There are many types, which are excited by oscillation. The method can be divided into a self-excited oscillator and a stimulator; according to the circuit structure, it can be divided into a RC oscillator, an inductor-capacitor oscillator, a crystal oscillator, a tuning fork oscillator, etc.; according to the output waveform, it can be divided into a sine wave and a square wave. Oscillators such as sawtooth waves. Widely used in electronics industry, medical, scientific research, etc. Mainly used in various universities, medical, petrochemical, health and epidemic prevention, environmental monitoring and other scientific research departments for biological, biochemical, cell, and bacteria. Oscillation culture of various liquid and solid compounds.
The speaker is the weakest device in the audio equipment, and it is the most important part for the sound effect. The variety of speakers is different, and the price varies greatly. The audio energy passes electromagnetic, piezoelectric or electrostatic effects. The paper cone or diaphragm vibrates and resonates (resonates) with the surrounding air to produce sound. According to the switching mechanism and structure, the split coil type (electric type), capacitive type (electrostatic type), piezoelectric type (crystal or Ceramic), electromagnetic (pressure spring type), electric ion type and pneumatic type speaker, etc. The electric type speaker has the advantages of good electroacoustic performance, firm structure and low cost, and is widely used. According to the sound radiation material, the paper basin and the horn Type, diaphragm type speaker; rounded, oval, double cone and rubber folding ring according to the shape of the paper cone; subwoofer, midrange and treble according to working frequency, and some are also divided into recorder, TV, ordinary and High-fidelity speakers, etc.; according to the voice coil impedance, low impedance and high impedance; according to the effect of direct radiation and ambient sound.
Regardless of whether the thief wears gloves or not, as long as the hand is close to the sensor of the burglar alarm 5~80mm, the alarm will immediately send out an alarm signal. The circuit is shown in the figure. The sensor is indicated by G in the picture, G and ground. There is a distributed capacitance Co, Co and L, C1, V1 constitute a three-point capacitor oscillator. In the loop composed of Co, C1, L, C0 and C1 are connected in series from the AC path. When no one is close to G When Co is small, when it is connected in series with C1, the partial pressure at both ends of Co is larger, and the partial pressure at both ends of C1 is smaller. The higher high-frequency voltage at both ends of Co is fed to the base of V1 through C3, which is enough to maintain The three-point oscillator generates oscillation. At this time, the voltage drop on R3 is high, so that V2 is turned on, and the composite tube composed of V3 and V4 is turned off, and the power of the four-sound analog integrated circuit IC is cut off, the IC does not work, and the speaker does not sound. When someone approaches the sensor G, the Co value increases, and the high-frequency partial pressure at both ends of Co becomes smaller. The voltage fed to the base of V1 through C3 is not enough to maintain V1 oscillation, and V1 stops immediately. At this time, on R3 The voltage drop is small, V2 is cut off, V3 and V4 are turned on, the 2 pin (Vss end) of the IC is equivalent to the grounding, the IC is energized, and the 3 pin outputs the siren sound signal. After the V5 is amplified, the sound is raised.
V1, V2, V3 adopt 3DG6, etc., B is 80~150; V4 adopts 3DG130, 3DG12 or 3DK4, etc. V5 adopts 9013, etc. The integrated circuit IC selects CW9561 four sound IC.VD1 is 2CP type M pole tube, Vw is 2CW12 stable The pressure diode.I is wound with a 0.31mm enameled wire on a plexiglass tube with an outer diameter of 10mm. The inductor G is made of a 200X150mm metal plate, or the G-point lead is connected to the metal door lock.
When debugging, first check if the V3 collector voltage is about 5V. If the difference is large, check if Vw is intact; if it is normal, you can start to adjust the sensitivity. Rotate KP1 to make the speaker sound, then adjust KP1 slightly to make BL just right. Do not vocal. At this time, when the hand is close to the copper piece G, the alarm should sound. When the hand leaves, the alarm will stop using the sound. Note that the sensitivity should not be adjusted too high, otherwise the circuit will be unstable.