Lm358 constant current source circuit
Lm358 circuit schematic
The LM358 includes two independent, high-gain, internal-frequency-compensated dual op amps for single-supply operation with a wide supply voltage range. It is also suitable for dual-supply operation. Under recommended operating conditions, the supply current is The power supply voltage is independent. Its range of applications includes sense amplifiers, DC gain blocks, and all other single-supply op amps.
The LM358 is available in a packaged 8-lead dual in-line and patch package.
Infrared detection alarm
The alarm can detect the infrared rays emitted by the human body, and when the person enters the monitoring area of ​​the alarm, an alarm sound can be generated, which is suitable for home, office, warehouse, laboratory.
Anti-theft alarms for more important occasions.
The circuit principle of the device is shown in Figure 1. It consists of an infrared sensor, a signal amplifying circuit, a voltage comparator, a delay circuit, and an audible alarm circuit. Infrared detection
When IC1 detects the infrared signal radiated from the front body, it outputs a weak electrical signal from pin 2 of IC1, and is amplified by a first-stage amplifying circuit through a triode VT1, and then input to the operational amplifier IC2 through C2 for high gain and low. The noise is amplified, and the signal output by the IC21 pin is strong enough. IC3 as a voltage comparator, it
The 5th pin is supplied with the reference voltage by R10 and VD1. When the signal voltage output from the IC21 pin reaches the 6th pin of IC3, the voltages of the two input terminals are compared. At this time, IC3
The 7th pin changes from the original high level to the low level. IC4 is the alarm delay circuit, and R14 and C6 form a delay circuit, which takes about 1 minute. When IC3's 7 feet become
When low, C6 discharges through VD2. At this time, pin 2 of IC4 goes low, which is compared with IC4's 3-pin reference voltage. When it is lower than its reference voltage,
The 1 pin of IC4 becomes high level, VT2 turns on, and the alarm BL energizes to sound an alarm. After the infrared signal of the human body disappears, the 7th pin of IC3 returns to the high level output.
At this time, VD2 is cut off. Since the voltage across C6 cannot be abrupt, it is slowly charged to C6 through R14. When the voltage across C6 is higher than its reference voltage, IC1 1
The foot goes low and the time is about 1 minute, that is, the alarm lasts for 1 minute.
The VT3, R20, and C8 form a power-on delay circuit, and the time is also about 1 minute. Its setting is mainly to prevent the user from immediately alarming after booting, so that the user has
Sufficient time to leave the surveillance site, while preventing false alarms when calls are lost after a power outage.
The device is powered by a 9-12V DC power supply, stepped down by T, full-bridge U-rectified, C10 filtered, and the detection circuit is powered by IC5 78L06. The device is AC and DC
Dual-use, automatic and uninterrupted conversion.
A prism (Prism) is an optical element that deflects light according to a specific angle between the emitted light and the incident light. In the optical path, the prism has the function of changing the angle between the emitted light and the incident light (such as deflection 90°, 180°, etc.), shifting the light and changing the direction of the image. Prisms are widely used in laser research, laser optical systems, optical imaging, machine vision, life sciences, biomedicine and other fields or products. United Optics can provide a variety of prism stock standard products, such as K9 standard precision Right Angle Prism, K9 high precision right angle prism, UV fused silica standard precision right angle prism, UV fused silica high precision right angle prism, K9 pentagonal prism, K9 Dove prism, K9 roof prism, K9 corner reflector (K9 corner prism), ultraviolet fused silica corner reflector (ultraviolet fused silica corner prism), wedge prism, etc.
The "dispersive prism" that decomposes the composite light into the spectrum in the spectrometer, the more commonly used is the equilateral prism; in the periscope, binocular telescope and other instruments, the direction of the light is changed to adjust the imaging position of the "total reflection prism". ", generally right-angle prisms are used.
Irregular Prism,Special-Shaped Prism,Octagonal Prism,Mini Prism
Bohr Optics Co.,Ltd , https://www.bohr-optics.com