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
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Recording circuit of phone conversations using PC
This circuit is used to record telephone conversations on your landline telephone. All you will need is this small circuit and subscription of your PC. There are few times when we forget what we said or told us. So we need recording. Sometime, not many years ago, recording of this kind of conversation was done with a small tape recorder. The...
This is a 8048/IM80C48 Microcomputer with 8 character 16-segment ASCII triplex liquid crystal display. The two bit character address is merged with the data and written to the display driver under the control of the WR line.
With this dataselector, only one RS-232 port is used to connect two RS-232 devices (i.e., printer, plotter, etc.) with a mini-or microcomputer. The operation is very simple. Power on will reset FFI (QFFT ~ Low), which enables gates N1, N5, and N7. Now communication between computer and device B is possible. Detection of the switch command,...
Circuits to interlace the Si7135 directly with two popular microprocessors are shown in Figs. 18-2a and b. The 8080/8048 and the MC6800 families with 8-bit words need to have polarity, overrange, and underrange multiplexed onto the digit 5 word. In each case, the microprocessor can instruct the ADC when to begin a measurement and when to hold...
The RGB blue box turns your PC"s RGB-monitor screen blue at the flip of a switch. That is, it makes your computer display bright white text on a blue background, instead of the usual low-intensity white on black. The RGB .blue box connects between your IBM PC color graphics adapter, or equivalent, and your RGB color monitor. By flipping a...
This circuit determines whether more than one input in a group of digital inputs is active. It provides a digital measure of the number of active inputs, and it allows you to establish a threshold for majority-decision applications. That is, whether the number of active inputs is more than, less than, or equal to a value between 1 and 15. You...
This RS-232 type line receiver to drive CMOS logic uses a Schmitt-trigger feedback network to ~give about 1-V input hysteresis for added noise immunity. A possible problem in an interface which connects two pieces of equipment, each plugged into a different ac receptacle, is that the power line voltage might appear at the receiver input when the...
The circuit uses one-half of a dual D flip-flop as an inverter. When the input decreases, the flip-flop resets, and its Q output increases. When the input increases, the reset line is released and Q gets clocked low. The rc delay between applying the input signal to the flip-flop"s reset input and its clock input enables clocking the flip-flop...
The IBM PC debugger plugs into the PC"s math-coprocessor socket.The 8288 bus controller, IC1, regenerates control signals from the processor"s status signals, SO, Sl, and S2. Reset LED Dllights if reset is active and holding the processor. Clock status LED D3 indicates that the processor is receiving a toggling clock signal.
This text-to-speech converter is built around the SP0256-AL2 speech processor and the Cf6256AL2 text-to-speech converter chips~manufactured by General Instruments. The circuit is set up to receive standard ASCII code from virtually any microcomputer or dumb tenninal that is equipped with an RS-232 port -such as a serial-printer or modem port....
The circuit, a general-purpose system with many uses, vocalizes 59 allophones contained in the speech processor. After filtering and amplification, its pulse-code-modulated output can drive an 8-!l speaker. The processor"s address pins, Al to A6, define 64 speech-entry points. Closing the test switch to the NAND gate lowers its output,...
The 555 acts as the tone generator configured in the astable mode. Its pin 3. square-wave output is transformed into a triangle wave by Rl and C2. The voice"s pitch is controlled by RL Transistor Ql can be 2N1086, 2N1091, or any other equivalent npn germanium type.
Dual 8051S Execute In Lock-Step
This hardware-software combination deletes clocks from the slave until both /iPs synchronize. The firmware
Reset Protection For Computers
This protection circuit is inserted between the reset switch and the motherboard. The earth connection of th
Z-80 Bus Monitor/Debugger
Getting microprocessor designs to work is notoriously difficult when both the software and hardware are new. The
Rs-232C Line-Driven Cmos Circuits
The circuit illustrates a way to power CMOS ICs from RS-232C lines. The MAX680 is normally used to genera
Glitch has been a universal slang expression among electronics people for an unwanted transient condition. In D/A converters, th
Buffer Lc Data And Clock Lines Circuit
The I2C serial bus is a popular two-wire bus lor small-area networks. I2C Clock and Data lines have open collector (or drain) outputs for each device-on the network. Only a single pull-up resistor is needed. With this arcliitecture, each device can talk on the network, rather than just listen. In some circumstances, it might be desirable to...
Laptop Computer Power Supply Circuit
A laptop computer supply that has 9-V output, crowbar overvoltage protection, and operates i`rom a 12-V supply is shown above. The supply voltage should be at least 3.6 V above the expected output voltage. Ql should be heatsinked appropriately. R5 should have a value of 1.5 1: for 9-V output. Table 1 gives values for other voltages. Note: Any...
Z80 clock circuit
The circuit will operate reliably from below 1 MHz to above 400 MHz. With Vcc = 5 V the output of the second inverter essentially attains a full swing from 0 V to 5 V. Such large logic output levels and broad frequency range capabilities make this oscillator quite suitable for driving MOS components such as CPU, controller chip, peripheral...
ADC0809 and PC bus interface circuit
ADC0809 is an 8-channel analog switch with an 8-bit successive approximation A/D converter. ADC0809 8-channel analog switches can be realized now 8 to 1, an address latch and d
AD574 and PC bus interface circuit
Another example given in AD574 and PC bus. The figure for the AD574 converter Ul, U2 is 74LS245 bidirectional data buffer, U3 of 74 Lsoo two-input AND gate, U4 to 74LS125 tri-s
The PC CPU overheating language caution circuit diagram
Circuit is shown. It consists of a temperature sensor, temperature control of electronic switches and circuits composed vocal language. In the hot summer season, PCs central pr
PC Serial Port Receiver
This circuit was designed to control a 32 channel Christmas light show from the PC serial port. Originally designed with TTL logic, it has been simplified using CMOS circuits to reduce component count. It is a fairly simple, reliable circuit that requires only 4 common CMOS chips (for 8 outputs), an optical isolator, and a few discrete...
Electrical Equipment Control UsingPC
Here is a novel idea for using the printer port of a PC, for con-trol application using software and some interface hardware. The interface circuit along with the given software can be used with the printer port of any PC for controlling up to eight equipment.
Laptop Computer Serial Port Power Booster
If you are looking at this page, you probably feel like I did when I tried to run a self-powered PIC programmer with my notebook computer. Yes, the serial port was the ultra-low-power type and wouldn`t provide enough current to power the programmer. The problem was clear and so was the solution. I could have modified the programmer to get the...
This is a page of analogue interfaces for joysticks. Although these interfaces have been developed for use with 4QD`s controllers they will have plenty of other uses. Also because of the development history, we have printed circuit boards available (either fully populated and tested) or bare boards) for these interfaces. All of 4QD`s Motor...
Blank Frank`s RS232 - Lowe HF-225 interface
If you have access to a Lowe HF-225 shortwave receiver, then you might be interested in this page. If you don`t, then you`d probably be better off leaving now. What follows is a project I completed some time ago, which allows the Lowe HF-225 to be controlled from a PC, or other device with an available RS232 port. The Rx has an input for a...
RS-232/485 converter has automatic flow control
The circuit in Figure 1 is an RS-232/485 converter that uses the transmitted signal itself to control the flow. The circuit uses MAX232 and MAX483 interface circuits, IC1 and IC2 from Maxim Integrated Products (http://www.maxim-ic.com) to convert between the ICs' respective signal levels and logic levels. Because both ICs invert the signal, the...
Whoever thinks about reproducing an interface for the Aladin, should first of all be aware of the fact that there are two different versions of the interface. The first version, easier to assemble, enables the user to transfer dive data from the Aladin to the personal computer. The other version, a more complex construction than the first one,...
AIU - Analog Interface Unit
The Analog Interface Unit (AIU) is a simple circuit that connects to a PC parallel port, and allows you to sample and output 8-bit analog signals under software control.
CCD Array Reader Project
The CCD Array Reader project began with a free sample of the Texas Instruments TC102-1 CCD Linear Image Sensor and its rather terse data sheet. The TC102-1 provides virtually no support circuitry, only the raw CCD (with a few special pixels) and a simple output buffer. The board shown below was designed to continously scan the TC102-1 and output...
USB Interface Circuits
Computer Interface Circuits
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...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity