VIEWSONIC G90fB 4 Model No VS10794 19” Digital Controlled Color Monitor Schematic Full

Viewsonic G90fB-4 Model No. VS10794 - 19” Digital Controlled Color Monitor_Circuit Diagram_[Full]

CPU 

SMPS

OUTPUT

VIDEO

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Heart Rate Monitor

Strictly speaking, this straightforward circuit shouldnt work! How may someone are expecting an extraordinary mild dependent resistor photograph cell to see via a fingertip in pure sunlight hours and discover the change in blood waft as the center pulsates? The secret is a excessive gain circuit, in line with a twin op amp IC which will additionally be both the low power LM358 or the JFET TL072. The LDR is attached in sequence throughout the 9V battery supply via a 100kO resistor (R1) and the minute signal due to the blood pulsing under the pores and skin is fed to the non-inverting (+) input, pin 3, of IC1a by manner of a 0.µF capacitor.

Pin three is biased via a excessive impedance voltage divider along with two 3.3MO resistors. The feedback resistors to pin 2 set the acquire to 11 instances. The output of IC1a is fed by implys of a zero.47µF capacitor and 220kO resistor to IC1b. This is configured as an inverting op amp with a acquire of forty five so that the full circuit acquire is set 500. The output of IC1b is used to drive an analog meter which is additionally a multimeter set to the 10V DC vary or any panel meter in series with a resistor to restrict the present to less than its full-scale deflection. The prototype used an old VU meter with a 47kO resistor fitted in collection.

Circuit diagram:

Heart Rate Monitor Circuit Diagram

Note that the unit used to be designed to use the Dick Smith Electronics gentle based resistor (Z-4801). Other LDRs may just require a transformation within the value of resistor R1. A gentle source this kind ofs a high brightness LED isn't required. All that is wanted is a reasonably well-lit room, preferably pure daylight, to provide a wholesome swing of the needle. Only when the fingers are very cold does it make it a little bit more difficult to competently rely the heart beats. To check your coronary heart rate, in moderation position your thumb or finger over the LDR and depend the meter fluctuations for a length of 15 2ds. Then multiply the end result with the aid of four to obtain your pulse charge. The circuit can no longer be used if you're walking or working, etc.

Author: Tony Lee - Copyright: Silicon Chip Electronics Magazine

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Non Contact Power Monitor

Here is a simple non-contact AC power monitor for home appliances and laboratory equipment that should remain continuously switched-on. A fuse failure or power breakdown in the equipment going unnoticed may cause irreparable loss. The monitor sounds an alarm on detecting power failure to the equipment. The circuit is built around CMOS IC CD4011 utilising only a few components. NAND gates N1 and N2 of the IC are wired as an oscillator that drives a piezobuzzer directly. Resistors R2 and R3 and capacitor C2 are the oscillator components. The amplifier comprising transistors T1 and T2 disables the oscillator when mains power is available. In the standby mode, the base of T1 picks up 50Hz mains hum during the positive half cycles of AC and T1 conducts.

This provides base current to T2 and it also conducts, pulling the collector to ground potential. As the collectors of T1 and T2 are connected to pin 2 of NAND gate N1 of the oscillator, the oscillator gets disabled when the transistors conduct. Capacitor C1 prevents rise of the collector voltage of T2 again during the negative half cycles. When the power fails, the electrical field around the equipment’s wiring ceases and T1 and T2 turn off. Capacitor C1 starts charging via R1 and preset VR and when it gets sufficiently charged, the oscillator is enabled and the piezobuzzer produces a shrill tone. Resistor R1 protects T2 from short circuit if VR is adjusted to zero resistance.

The circuit can be easily assembled on a perforated/breadboard. Use a small plastic case to enclose the circuit and a telescopic antenna as aerial. A 9V battery can be used to power the circuit. Since the circuit draws only a few microamperes current in the standby mode, the battery will last several months. After assembling the circuit, take the aerial near the mains cable and adjust VR until the alarm stops to indicate the standby mode. The circuit can be placed on the equipment to be monitored close to the mains cable.

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