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
Meter Counter Circuits
Fundamentals of Electrical Engineering and High-impedance voltmeter
USB RGB LED VU Meter
This project creates a RGB LED VU Meter which is controlled via USB by a Windows 7 or Vista host machine. The project serves several purposes: Firstly, it demonstrates how to read audio information from the Windows machine and pass this over USB to the device (which is a question which popped up several times after my USB Performance Monitor proje
PC RLC Meter (BETA) Builders
50 MHz frequency counter voltage meter & SWR/PWR indicator
This is a successor of the PIC16C71 4-digit LED f-counter & V-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device PIC16F876. The later is capable of driving 4 digit LED display in multiplexed mode while measuring fr
Peak Reading Audio Level Meter
Using minimum component count; this simple circuit will indicate peak audio response on an analogue meter, similar to a tape recorders meter. The circuit uses an op amp as a non inverting amplifier, but with one addition - a diode in the feedback loop. The circuit has a fast response time and slow decay time to indicate peak readings. The 1N4148 d
RF Probe and Watt Meter
This RF probe can be used at High Frequency (HF) or Ultra High Frequency (UHF) on both 50 and 75 ohm coaxial cables. In addition the RF voltage can be measured under load or no-load conditions which allows the circuit to double as an RF Watt meter. The RF probe can be used for oscillators and small transistors for powers up to 2 Watts. The circuit
Module thermometer temperature meter for digital multimeter using the ic lm35
Converser of temperature tension. To be used with a digital multimeter with reach from -40 °C to 110 °C. With checker of the state of it laughed and a without any adjustment, thanks to LM35! The ice is founded the 0 °C and the point of ebullition of the water, at sea level it is of 100 °C. Using those two point of reference is gauged the temperatu
Enclosure for the Magnetometer v2.0
The magnetometer was moved to an outdoor location and a specialized enclosure was built. An accessory temperature controller was included to maintain a constant temperature and digital link was created to ferry the recorded data back into the laboratory. During the August-September 2000 refurbishment, the magnetometer was moved from the...
DC Motor Controller and Tachometer
Controlling the speed of a motor is very important in many situations especially in robotics. There are many techniques of controlling the speed of motors, each with their advantages and disadvantages. This document will show you how to build a motor controller which controls the speed of a motor by varying the input voltage. Along the same lines,
Linear AC voltmeter circuit diagram
The use of diode rectifiers in AC voltmeters with a low lower limit of measurement range (0. 5. 1 V) leads to significant nonlinearity of the scale because of the nonlinearity of current-voltage characteristics of diodes. The use of electronic amplifiers in rectifier circuits allowing to linearize the scale but requires a power supply. At the...
VOLTMETER WITH IMPROVED LINEARITY CIRCUIT DIAGRAM
The device uses a microammeter with full scale deflection of 50 uA and with the resistance of 2 kilohms. The upper limit of the measuring range of the voltmeter is 1 V, and in the range of 0. 2. 1 V the measurement error due to the nonlinearity of the scale is less than 1% of the full scale range. By selection of the resistor R3 values the...
For many years, the Q meter has been an essential piece of equipment for laboratories engaged in the testing of radio frequency circuits. In modem laboratories, the Q meter has been largely replaced by more exotic (and more expensive) impedance measuring devices and today, it is difficult to find a manufacturer who still makes a Q meter. For the r
Frequency Meter Circuits
VU Meter 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