Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Digital to Analog Circuits
Analog to Digital Circuits
Data Logging Circuits
Data Bus Circuits
Ultrasonic range finder
An ultrasonic, or sonar, range finder is a common sensor in robotic systems and industrial environments. Even home and automotive uses are possible. A novel sensor design consists of a WC, a few peripheral components, and a pair of ultrasonic transducers (Figure 1). The range-finder module consists of a WC, a transmitter, a receiver, a...
Interfacing DS2155 to MPC8260
Application Note 381 contains information necessary to interface the Motorola MPC8260 processor to the DS2155 T1/E1/J1 Single Chip Transceiver (SCT). The application note covers interfacing both the address and data processor bus and the communications serial bus. Interfacing the processor bus of the MPC8260 to the DS2155 is straight forward and...
MAX1407 Complete Data Acquisition System
A design example for a portable data acquisition system is offered that greatly simplifies the circuit design task. A reduction from seven components down to three components is accomplished with a design that has lower system cost, faster time-to-market, smaller size, better performance, and higher reliability.
Data Conversion, Interface and Signal Conditioning
Like its predecessor, AN67, this Application Note includes circuits for high speed video, interface and hot swap circuits, active RC and switched capacitor filter circuitry and a variety of data conversion and instrumentation circuits.
Keyboard data-acquisition system
The most important criteria of a data-acquisition system for college science laboratories are simplicity and price rather than precision or speed. The data-acquisition system in Figure 1 offers adequate precision of less than 0.5% and speed of 1 Hz to replace the outdated laboratory chart recorder in student laboratories. You can install the...
Small Lie Detector
Here`s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie.
Data Conversion, Interface and Signal Processing
Application Note 67 is a collection of circuits from the first five years of Linear Technology, targeting data conversion, interface and signal processing applications. This Application Note includes circuits such as fast video multiplexers for high speed video, an ultraselective bandpass filter circuit with adjustable gain and a fully...
The circuit diagram of the Lie Detector is shown above. It consists of three transistors (TR1 to TR3), a capacitor (C1), two lights or LEDs (L1 & L2), five resistors (R1 to R5), and a variable resistor (VR1). This circuit is based on the fact that a person`s skin resistance changes when they sweat (sweating because they`re lying). Dry...
Precision Digital Altimeter
The current concept incorporates a wireless transmitter and receiver and is thought to be used for remote controlled airplanes or appliances with two seperate parts. In other words, we have one dedicated transmitter (acquisition, filtering) and one dedicated receiver part (user-interface, look-up table, calibration, storage), capable of being...
Digital-Output Sensor Simplifies Temperature Acquisition
The TMP03* is a complete temperature data-acquisition system on a monolithic silicon chip. Including a silicon-based sensor, internal voltage reference, and sigma-delta A/D converter, it fits in a 3-pin (power, common, and output) TO-92 transistor package. Its digital output is a low-frequency variable-duty-cycle serial data stream, available at...
Data-acquisition system uses fault protection
Sensitive systems, such as those in aircraft, must withstand fault conditions, thereby avoiding component and system damage, because a sensor failure could cause a catastrophic event to occur. A channel protector, comprising two n-channel MOSFETs connected in series with a p-channel MOSFET, can protect sensitive components from voltage...
Data-acquisition circuit measures everything
Using a product developed for PC-motherboard environmental monitoring, you can configure a low-cost, general-purpose DAS (data-acquisition system) (Figure 1). The DAS can directly monitor multiple voltage channels as well as temperature and frequency. It can also directly monitor digital sensors. Using only a few additional components, the...
Data Acquisition Circuits
This application note features 8-, 10-, and 12-bit data acquisition components in various circuit configurations. The circuits include battery monitoring, temperature sensing, isolated serial interfaces, and microprocessor and microcontroller serial and parallel interfaces. Also included are voltage reference circuits (Application Note 42...
16-Channel, 24-Bit Accurate Solutions for Data Acquisition
The circuit in Figure 1 shows the versatility of the LTC2418. A combination of single-ended, differential, unipolar and bipolar input sources are simultaneously applied to the LTC2418.
Below is a rough schematic of the layout of the accelerometer PC board looking from the component side. The microcontroller is an Atmel AT89S8252, an 8051 clone. This microcontroller is in-circuit programmable using an SPI interface. The SPI pins are also used to drive the MMC. To permit the dual use there is a jumper block (located below the...
PC-Based Data-Acquisition Board
This application note describes techniques of using a PC based Digital I/O Board to characterize analog-to-digital converters (ADCs). It will look at static DC parameters such as integral nonlinearity (INL), differential nonlinearity (DNL), gain, and offset errors, but also noise, internal reference voltage, and channel-to-channel coupling and...
Analog-Signal in Industrial Automation
Industrial control systems continue to employ standard analog signals for transmitting data between the process and the control equipment. Robust, 4-to-20mA current-loop signals that are easily transmitted over several thousand feet, ±5 and ±10V signals are also very common in industrial systems. This application note showcases Maxim`s...
Single-Ended Signal Conditioning Circuits
The LTC®2400 is the industrys first No Latency TM ADC that combines automatic offset and full-scale calibration, an internal oscillator, a sinc4 digital filter, and serial I/O to yield a 24-bit ADC with 1.5µVRMS input noise and singleshot conversion time architecture. It is the ideal A/D converter for temperature measurement and high...
Low-Jitter Clock for High-Speed Data Converters
Figure 1 illustrates the simplified block diagram of a typical high-speed data converter system. The system consists of a bandpass filter, ADC, high-frequency clock, high-speed storage device, and post processing unit. Aside from the MAX104, the high-frequency clock plays a significant role in determining the accuracy of a high-speed data...
visible optical link for RS-232C
The design in Figure 1 is a visible optical link for those who need to see the transmitted data. An isolation figure of more than 5000V is a bonus. Tests of the system used the COM input of a data-acquisition system, as well as a standard PC`s COM port. The MC1489 converts the RS-232C data to TTL signals. A 7404 gate then inverts the signal. The...
PC monitors two-way RS-232 transmission
The method in Figure 1a needs no access or knowledge of the communicating devices. A C program opens two COM ports and installs interrupt-service routines for IRQ4 and IRQ3. Upon the reception of an interrupt, the routine stores a byte in a common circular buffer with the COM identifier and error flags. The main program displays the contents of...
3.3V & 5V Regulator to Run Computer & RS232
The circuit consists of two sections, one being a DC/DC converter and the other being a pair of dual N-channel MOSFETs and their associated high-side drivers that effectively form a DPDT switch.
RS232 Interface Circuits
The rapid, widespread use of 3.3V logic circuits complicates the selection of RS232 interface circuits. The optimum choice of an interface circuit should be based upon several application dependent factors: 1) Logic circuitry connected to interface chip 2) Power supply voltages available 3) Power consumption constraints 4) Serial...
RS232/RS485 Multiprotocol Transceiver
The RS232 transceiver supports both RS232 and EIA-562 standards, whereas the RS485 transceiver supports both RS485 and RS422 standards. The logic input (MODE) selects between RS232 and RS485 modes. With three additional control logic inputs (RXEN, DXEN and ON), the LTC1387 adapts easily, as shown in Table 1, to various communications...
RS232 Connections wiring up
While the normal PC hardware might well run with just Tx, Rx and Ground connected, most driver software will wait forever for one of the handshaking lines to go to the correct level. Depending on the signal state it might sometimes work, other times it might not. The reliable solution is to loop back the handshake lines if they are not used.
RS-232 Powered Temperature Sensor
A state-of-the-art silicon temperature sensor like MAX6577 measures a remote temperature far from the host system. The temperature sensor converts this temperature into a square wave with a frequency proportional to the absolute temperature of its package, while drawing little supply current from the power source. The amplitude of the output...
RS485-like multi-drop bus
PBUS is an RS485-like multi-drop bus for interconnecting PIC and other microcontroller-driven devices. Protocol and software is written by Jap. Just include a separate pbus library file into your project and add your command handlers for the specific device in a few lines.
RS232 Transceivers circuits
Hand held computers are rapidly moving to 3V logic to save power. Yet higher voltage buses are still utilized elsewhere in the system for display driving and other functions. The LT1330 is functionally equivalent to the LT1237 but operates from 5V with a separate logic supply to interface directly with 3V logic.
Figure 1 shows a simple, cost-effective way of providing these bias voltages. A step-up regulator, IC1, forms the heart of the circuit. This regulator switches at a constant frequency of 1 MHz and a fixed duty cycle of 70%. IC1 steps up the input voltage to 5V by storing the energy in the inductor when the internal MOSFET, M1, is on and...
Circuit controls brightness of multiple displays
I recently needed to control nine seven-segment displays for a microcontroller`s serial port. The complication I faced was the need to provide a continuous brightness adjustment for all the digitsfrom completely dark to fully bright. I couldn`t easily use the obvious solution of a string of 74HC595 serial-to-parallel converters driving the...
Circuit tests VCOM drivers
Flat-panel LCD monitors offer excellent image quality and more compact form factor than CRTshence, their steadily increasing popularity. Unfortunately, the complexity of their manufacturing process makes LCD monitors considerably more expensive than CRTs. The amplifier that drives VCOM, the voltage on the backplane of the LCD panel, must be able...
LCD Serial Terminal
This project is a self-contained serial terminal using a PIC16F84 microcontroller chip, an inexpensive LCD character display, a keypad, and very little else. It is full-duplex, meaning keypresses cause RS-232 output, and RS-232 input makes characters appear on the LCD. If you connect the RS-232 output to the input you can see the keys as you...
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
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