Vacuum Tubes Valves
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Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
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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
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Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
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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
Finite State Machine Programmable Logic Controller
I have had this project hanging around for ages and have tried to submit it for publication without much enthusiasm so I will make everything available here for the individual constructor. The complete Pascal source code for the compiler program is available below.
A Hierarchical Priority Encoder
Anormal priority encoder encodes only the highest-order data line. But in many situations, not only the highest but the second-highest priority information is also needed. The circuit presented here encodes both the highest-priority information as well as the second-highest priority information of an 8-line incoming data. The circuit uses the...
Interfacing Sony control stick to Empeg
You may find that there are too few, if your power is very noisy (as can happen in a car environment) it may help to place a 0.1uF and/or 10uF capacitor before and/or after the voltage regulator. At the moment I`m not using these but at this point I`ve only tested it on the bench, not in the car. I`ll update this web page after it`s all installed.
508A microcontroller can deliver a maximum of 25mA
A typical device that requires less than 5v and draws less than 25mA is an LED. A LED must be supplied with an exact voltage for it to operate correctly. Because it requires LESS than 5v, a dropper resistor (current limiting resistor) must be included in series to "take-up" or "absorb" or "interface" the LED to the output line. Working out the...
Replacement For The LM3909 LED Flasher / Oscillator
This page features a replacement circuit for the LM3909 LED Flasher / Oscillator using discrete components. The circuit is functionally the same as the integrated LM3909 but has a minor variation of the components used. Naturally the circuit will not be as physically as compact as the integrated circuit but it does offer the ability to adjust...
Logic offers complementary-switch control
The circuit in Figure 1 provides not only a complementary drive signal but also a deadtime delay on both rising and falling edges. The high-speed inverter gates use IC1, a 74HC04 CMOS circuit, and 1N5819 Schottky diodes D1 and D2. The 74HC04 inverter features symmetrical input thresholds, VIHMIN and VILMAX, at 70 and 30% of the supply voltage,...
Logic PSU with Overvoltage Protection
The 5 volt regulated power supply for TTL and 74LS series integrated circuits, has to be very precise and tolerant of voltage transients. These IC`s are easily damaged by short voltage spikes. A fuse will blow when its current rating is exceeded, but requires several hundred milliseconds to respond. This circuit will react in a few microseconds,...
Make a DAC with a microcontroller`s PWM timer
Many embedded-microcontroller applications require generation of analog signals. An integrated or stand-alone DAC fills the role. However, you can often use PWM signals for generating the required analog signals. You can use PWM signals to create both dc and ac analog signals. This Design Idea shows how to use a PWM timer to simultaneously...
DAC`s outputs from single-ended to differential mode
High-speed DACs, such as Analog Devices` AD9776/78/79 TxDAC family, offer differential outputs, but, for low-end ac applications or high-precision level-setting applications, a single-ended current-output DAC with a differential-conversion circuit provides a novel approach to generating differential-waveform-control functions.
Recording Power Cycling Information Using the DS1602/DS1603
The DS1602 and DS1603 from Dallas Semiconductor offer a simplified hardware solution for keeping time as well as tracking powered up time of a system. The DS1602 and DS1603 can be read and written directly by a microprocessor or microcontroller using simple software; however, a more creative software algorithm can be used to track years, months,...
DAC and Op Amp Generate Variable Negative Control Voltage
This design idea describes a simple circuit to generate a programmable negative control voltage. It takes the output of a single supply digital-to-analog converter (DAC) and produces a variable negative voltage. The DAC output from 0V to +2.5V is converted to 0V to -5V at the output. These early DACs (such as the MX7837/MX7847 and MAX523)...
Interface Design DS2151 and DS2152
The transmitter output drivers present a low impedance to inbound surges and must be able to drive sufficient current in the primary of the transmit transformer in order to produce the required output pulse at the network interface. The receiver inputs present a high impedance to inbound surges and require very little input current to operate....
DAC and op amp provide variable-control voltage
Early DACs contained standard R-2R ladder networks, and produced a negative output voltage. These early DACs, such as the MAX7837/7847 and the MAX523, require both positive and negative supply rails to accommodate their negative output. With the transition to single-supply ICs, however, many modern DACs operate with a single supply rail and an...
DDS IC plus frequency-to-voltage converter make low-cost DAC
Precision DACs are essential in many consumer, industrial, and military applications, but high-resolution DACs can be costly. Frequency-to-voltage converters have good nonlinearity specificationstypically, 0.002% for the AD650and are inherently monotonic. This Design Idea shows how you can use a frequency-to-voltage converter and a DDS...
Deglitching Techniques for High-Voltage R-2R DACs
In an R-2R DAC design with supply voltages exceeding ±5V, large voltage glitches (up to 1.5V) can occur during the DAC`s major-carry transitions. These glitches can propagate through the output buffer amplifier and appear at output. The slewing of the level shifters that control the top (VREF+) and bottom (VREF-) single-pole double-throw...
Digital-Analog Converters Are a "Bit" Analog
Despite the popularity of digital devices, real world signals are typically represented by analog signals. Digital control systems process real world analog signals by using an analog-to-digital converter (ADC) to convert analog signals to digital. Conversions back to analog signals are accomplished using a digital-to-analog converter (DAC)....
Double DAC rate by using mixers as switches
You can effectively double the sample rate of a DAC by interleaving two DACs into a single unit. Updating each DAC on an alternating basis and switching to the appropriate output double the effective throughput of the overall system. It is essential to overall performance that you use a high-quality, high-speed switch in the multiplexing of the...
DPPs make nonvolatile microvolt DAC
The availability of a seemingly limitless variety of monolithic DAC chips makes it easy to implement most digital-to-analog-conversion applications with a single off-the-shelf device. Sometimes, an unusual set of requirements necessitates a multichip approach, however. One example of such a requirement is the need for nonvolatility of the DAC`s...
Dual, Voltage-Output DAC Consumes Miniscule Power
The dual, voltage-output DACs shown in the figure below employ a combination of power-conserving tricks to draw less than 20µA from a 5V supply. The circuit suits a need for programmable voltage generation in slow or static applications, such as the nulling of offsets in a micropower instrument.
Force/Sense DAC Applications
This article discusses application circuits for Maxim force/sense digital-to-analog converters (DACs). Applications include: selectable fixed-gain DAC, programmable gain DAC, photodiode bias control, amperometric sensor control, digitally programmable current source, Kelvin load sensing, temperature sensing, and high current DAC output. A brief...
Methods of Controlling Laser Drivers: POTs and DACs
A laser module designer can use a fixed resistor, mechanical pot, digital pot, or a digital-to-analog converter (DAC) to control the laser driver`s modulation and bias currents. The advantages of a programmable method (POT or DAC) are that the manufacturing process can be automated and digital control can be applied (e.g., to compensate for...
PC and DACs generate two simple analog outputs
The simple and inexpensive circuit in Figure 1 generates two PC-controlled analog reference voltages. You supply a wall-adapter supply and a parallel connector, and the circuit is ready to run. The circuit uses two 12-bit AD7243 DACs, which require only one supply voltage. These converters also include internal references, minimizing the number...
Use a DAC to vary LVDT excitation
LVDTs (linear variable differential transformers) are electromechanical measuring devices that convert the position of a magnetic core into electrical signals. You generate these signals via excitation on the primary side. The results on the secondary sidetypically, two secondary windingsdepend on the position of the core (Figure 1).
555 Timer as an A/D converter
I had a Basic Stamp project that needed to measure a nominal 12 volt battery, and I wanted a simple solution. This is the simplest I could come up with. The 555 timer will put out positive pulses. The pulse width is inversely proportional to the difference in voltage between the voltage at "ANALOG IN" and the voltage of the 4.7uF capacitor(let`s...
16-bit ADC provides 19-bit resolution
Long-distance optical communications and medical equipment, such as CT scanners, can benefit from a fast and accurate data-acquisition system. Optical power systems, such as laser pumps, need to constantly monitor their power levels. In such systems, the incoming laser-power range and the laser control-loop response time are such that the system...
12-Bit Sampling A/D Converter Conserves Power
This application note uses a timer IC (ICL7555), CMOS logic and discrete transistors to automatically control the conversion the MAX190 12-bit SAR analog-to-digital converter (ADC). The delay between conversions can be programed using a resistor. Logic circuits ensures proper startup when power is applied.
How ADC Errors Affect System Performance
Using a 12-bit-resolution analog-to-digital converter (ADC) does not necessarily mean your system will have 12-bit accuracy. Sometimes, much to the surprise and consternation of engineers, a data-acquisition system will exhibit much lower performance than expected. When this is discovered after the initial prototype run, a mad scramble for a...
ADC controls multiple stepper motors
Typical stepper-motor control circuits use either logic gates and flip-flops or shift registers to generate the proper sequences of binary codes that produce bidirectional stepper-motor movement. A conventional stepper-motor-control circuit uses a square-wave generator, a sequence generator, or a shift register and current translators to control...
ADC enables temperature-compensated weigh-scale measurements
You can provide temperature compensation in weigh-scale applications by simultaneously measuring both the temperature of the bridge and the primary output of the bridge transducer. Traditionally, an integrated multiplexer connects multiple input variables to a single sigma-delta ADC. Each time the multiplexer switches the input, the ADC must...
ADC-to-PC interface transfers data in nibbles
The circuit in Figure 1 uses a Centronics printer port to interface an eight-channel, 8-bit ADC to a PC. The circuit cuts the cost of addressing and decoder circuitry and saves one expansion slot for interfacing. The design uses three of the subport`s various signals as control signals for channel selection, handshaking, and data transfer to the...
ADCs for Simultaneous Sampling
The MAX125 and the MAX126 are complete 14-bit data-acquisition systems in which four of eight inputs are tracked and held simultaneously (Figure 1). An on-board sequencer allows the user to program which four (or fewer) channels are to be digitized. Throughput rates range from 250ksps for one channel to 76ksps for all four channels. The input...
Automating ADC Data Collection
This article describes an automated data collection system for analog-to-digital converters (ADCs). It discusses the advantages of automating data collection as well as a detailed description of the hardware and software. It goes on to explain the operation of the system and give some data examples.
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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