Meter Counter Circuits
This circuit provides a low cost and reliable method of testing zener diodes. RVl can be calibrated in volts, so that when LED 1 just lights, the voltage on pins 2 and 3 are nearly equal. Hence, the zener voltage can be read directly from the setting of RVl. The supply need only be as high a value as the zener itself
The circuit tests whether or not a diode is open, shorted, or functioning correctly. If lamp A lights, the diode under test is functional. When lamp B is lit, the diode is good but connected backwards
Sensitive rf voltmeter
This circuit measures RF voltages beyond 200 MHz and up to about 5 V. The diode should be mounted in a remote probe, close to the probe tip. Sensitivity is excellent and voltages less than 1 V peak can be easily measured
Precision calibration standard
An external power supply that gives a voltage higher than the highest expected rating of the zener diodes to be tested is required. Potentiometer RVl is adjusted until the meter reading stabilizes
Visual modulation indicator
Indicator lamp brightness varies in step with modulated RF signal. Adjust R2 with transmitter on (modulated) until the lamp flashes in step with modulation
Power meter 1KW
The circuit is intended for 117 Vac Â± 50 Vac operation, but can be easily modified for higher or lower voltages. It measures true (nonreactive) power beingdeliveredto the load and requires no external power supply. Idling power drain is only 0 W. Load current sensing voltage is only 10 mV, keeping load voltage loss to 01%, Rejection of reactive...
Low resistance continuity tester
This tester can be used to check IC printed circuit boards. Two 4 K resistors and the transistors connected to them prevent current flow through the operational amplifier until the probe circuit is completed
Linear scale ohmmeter
One preset resistor is used for all the ranges, simplifying the setting up. Diode clamping is included to prevent damage to the meter if the unknown resistor is higher than the range selected
Peak detect and hold
If the voltage at the input exceeds the voltage on the capacitor, then the output of the 741 goes positive, the diode conducts, and the capacitor is charged up to the input voltage-forward voltage drop of diode. When the voltage at the input is less than that on the capacitor, the output of the 741 goes negative, and the diode cuts off
Sample and hold
The JFETs, Ql and Q2, provide complete buffering to Cl, the sample and hold capacitor. During sample, Ql is turned on and provides a path, rds(on), for charging Cl. During hold, Ql is turned off, thus leaving Ql Id (< 100 pA) and Q2 Igss (< 100 pA) as the only discharge paths
High speed sample and hold
This circuit exhibits a 10 V acquisition time of 900 ns to 0% accuracy and a droop rate of only 100 Âµ-V/ms at 25Â° C ambient condition. An even faster acquisition time can be obtained using a smaller value hold-capacitor. By decreasing the value from 1000 pF to 220 pF, the acquisition time improves to 500 ns for a 10 V step
The circuit charges and discharges a capacitor at a crystal-controlled rate, and stores on a sample-anddifference amplifier the change in voltage achieved. The current that flows during the discharge cycle is averaged, and ratiometrically measured in the a/d using the voltage change as a reference. Range switching is done by changing the...
U1a is an oscillator and U1b tbe measurement part of tbe circuit. It converts unknown capacity into a pulse-width modulated signal the same way anÂ·automotive dwell meter works. The meteris linear so tbe fraction or percentage of time that tbe output is high is directly proportional to the unknown capacitance (CXin the schematic).
The two-pole, five-position switch, coils and 365-pF variable capacitor cover a range from 1.5 to 30 MHz. The amplifier uses Darlington npn transistors whose high beta, 5000, provides high sensitivity with Sl used as the amplifier on/off switch. Switch S2 in the left position allows the output of the 1N34 diode to be fed directly into the...
The untuned, but amplified FSM can almost sense that mythical flea"s whisper-from 3 through 148 MHz no less-and yet, is so immune to overload that the meter pointer won"t pin. The key to the circuit is the amplifier, a 324 quad op amp, of which only one section is used.
The circuit monitors and displays a digital signal"s duty cycle and provides accuracy as high as Â±1%. Using switch S2, you can choose a frequency range of either 250 Hz to 2. 5 kHz at Â±1% accuracy or 2 kHz to 50 kHz at Â±10% accuracy. The common-cathode display gives the signal"s duty-cycle percentage. Phase-locked loop re4 and counters...
This circuit is designed around a 4049 hex inverter/buffer. Two inverters are used ina dual-frequency signal-injector circuit, another inverter is used as a logic probe, and the remaining three inverters are used as a sensitive dual-input, audio-signal tracer. The signal-injector portion gates are configured as a two-frequency,...
The Hewlett-Packard HSCH-3486 zero-bias Schottky diode is used as the detector. To avoid using a modulation method of detection, a chopperstabilized op amp is used. The chopper op amp basically converts the input de voltage to ac, amplifies it, and converts it back to de. Amplifying the de output from the detector 150 times with a chopper...
The circuit is based on the grid-dip or absorption effect, which occurs when a parallel resonant circuit is coupled to an oscillator of tbe same frequency. Ql operates in a conventional Colpitts oscillator circuit at a fixed frequency of approximately 4 MHz. A meter connected in series with tbe transistor"s base-bias resistor serves as the...
In machine and equipment design. some applications require measurement of both the shaft speed and the direction of rotation. Fig. 56-4 shows the circuit of a tachometer, which also indicates the direction of rotation. The flywheel has two magnets embedded in the outer rim about 45Â° apart. One magnet has the north pole toward the outside and...
This circuit operates by charging a small capacitor from a constant-current source when the pulse to be measured is present. Dual pnp transistor Q3 is the current source; its output current equals the LM329 reference voltage divided by the resistance of potentiometer Rl. When the input is high with no pulse present, Ql keeps the current...
The design shown is a simple unit for QRP operation on all authorized frequencies up to 30 MHz. based on a toroidal transformer Tl. The secondary winding of Tl samples a small amount o1 rf power. both forward and reflected, which is divided by the bridge circuit and rectified by diodes Dl and D2. Forward and reflected readings are obtained...
The circuit in Fig. 56-lla lights the signal lamp upon detecting a line current consumption of more than 5 mA, and handles currents of several amperes with appropriate diodes fitted in the D1 and D2 positions. Transistor T1 is switched on when the drop across Dl/D2 exceeds a certain level. Diodes from the well-known 1N400x series can be used...
The circuit outputs power to the drive motor when one or no sheets are being fed, but interrupts motor power when two or more superimposed sheets pass through the optodetector slot. The optodetector can be either an H2aB darlington interruptor module or an H23B matched emitter -detector pair. The output from the optodarlington is coupled to a...
The CS209 is designed to detect the presence or proximity ofmagnetic metals. It has an internal oscillator that, along with its external lc resonant circuit, provides oscillations whose amplitude is dependent upon the Q of the lc network. Close proximity to magnetic material reduces the Q of the tuned circuit, thus the oscillations tend to...
In this application, the ICM7249 is configured as an hours-in-use meter and shows how many whole hours of line voltage have been applied. The 20-MD resistor and high-pass filtering allow ac line activation of the SIS input. This configuration, which is powered by a 3-V lithium cell, will operate continuously for 21/z years.
A transducer senses a direct current magnetically, providing isolation between the input and the output. The detecting-and-isolating element is a saturable reactor, in which the input current, to be measured, passes through a one-tum control coil. The transducer provides an output of 0 to 3 Vdc, an input current of 0 to 15 Adc, and consumes...
This design is for an external signal strength meter that is analog, digital, and audible for mobile transmitter hunters. The S meter also incorporates a gain circuit. The digital LED bar graph display has a very fast response time. The 3.3-KO resistor near LM3914 can be replaced with a 5-K pot to control LED brightness. The S2A position...
Remote, noncontact, measurement of the speed of rotating objects is the purpose of this simple circuit. Linearity and accuracy are extremely high and normally limited by the milliammeter used and the initial calibration. This circuit is configured to count the leading edge of light pulses and to ignore normal ambient light levels. It is designed...
The adapter allows four inputs to be displayed simultaoeously on a single trace scope. For low-frequency signals, less than 500Hz, the adapter is used in the chop mode at a frequency of 50 kHz. The clock can be run faster, but switching glitches and the actual switching time of the DG201A limit the maximum frequency to 200 kHz. High...
This circuit turns a common oscilloscope into a versatile eight-channel display for direct voltages. The trend of each of the eight input levels is readily observed, albeit that the attainable resolution is not very high. The circuit diagram shows the use of an eight-channel analog multiplexer IC1, which is the electronic version of an...
The calibrator can be used to check the accuracy of a time-base generator, as well as to calibrate the input level of amplifiers. The calibrator consists of an NE555 connected in the astable mode. The oscillator is set to exactly 1 kHz by adjusting potentiometer P1 while tbe output at pin 3 is being monitored against a known frequency...
Frequency Meter Circuits
VU Meter Circuits
Low Cost Pulse Generator circuit
This pulse generator produces square pulses from 1Hz to 100KHz with adjustable pulse width of nearly 0-100%. The generator is powered with a voltage of 5-15V and is therefore suitable for both TTL and CMOS circuits. If you want to measure the response of an amplifier or give timing pulses to a variable frequency digital circuit or drive a pulse...
Key Code Combination High Security Door Lock
This project is an electronic lock with many combinations that you can easily change and opens only with the correct combination of four consecutive numbers. The big advantage of the electronic lock is that the four numbers must be entered in the correct order one after the other. If a number is wrong then the circuit automatically resets to its...
Induction Balance Gold Metal Detector Circuit
This circuit really is the simplest inducer balancing metal detector (IB, Inductlon Balance) that can be built. The LB metal detection method has a satisfactory depth of penetration and good distinction between iron-based and noble metallic objects. Several metal detectors are available in the market, but their price is often prohibitive for...
Secret High Power Free Energy Circuit (AEC)
This is a Tesla/joule thief hybrid circuit that its inventor claim to produce 90 times the input power! The circuit can be self looped and can provide 1050W of power. from the 1050W only the 11.6W will loop back to supply the joule thief. If you remove the bridge rectifier and the C capacitor you can use the circuit with high frequency AC...
High Power Full Bridge Flyback Driver circuit
You need to find a reliable full bridge driver to drive your flyback transformer? Well, This is your final stop. There are many flyback drivers schematics out there, but most of them will not last for long. It is common known that famous ZVS invented by Vladmiro Mazilli, is the most reliable flyback driver as it uses the resonant zero voltage...
High Precision Digital Pulse Meter Circuit
This small device, intended primarily for modellers, allows an instant reading of the time I of a pulse in ms. It can, for example, measure the position of the servomotors, about 1 to about 2 ms, or make repetitive or non-pulsed measurements, such as closing or opening times of any instrument, parasitic abnormality. The diagram just describes...
Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
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
Fluke provides interactive Digital Multimeter selection tool
May 15, 2017
Test and Measurement: Three emerging trends in the global test market
May 19, 2017
SatatonMall Offers Wide Range of a-Grade, Professional Textile Testing Instruments
May 19, 2017
A Three-Year Battle with Radon
May 9, 2017
Volkswagen Amarok Core 2017 review : off road test
May 17, 2017
Top 10 Tools Every Electrician Needs: Training the Apprentice
May 17, 2017
10 Home Kits That Test the Safety of Your Tap Water
Mar 8, 2017
Guitar Shop 101: Five Ways to Use a Digital Multimeter
Jan 8, 2016
Analogue Oscilloscopes and Measurements
Transmitters and Receivers
Sensors and Detectors
Sequential Pattern-ANSI Standards
Low Frequency Power Amplifiers
IC Regulated Power Supply
Digital Circuits 1
Digital Circuits 2
Digital Circuits 3
Digital Interconnection and Timing 1
Digital Interconnection and Timing 2
Digital Signal Integrity 1
Digital Signal Integrity 2
Digital Signal Integrity 3
Digital Signal Integrity 4
Digital Signal Integrity 5
Digital Memories 1
Digital Memories 2
Digital Memories 3
4 Band Resistor Calculator
5 Band resistor Calculator
6 Band resistor Calculator
Parallel Resistors Calculator
LED resistance Calculator
Resistors Calculator of Inverting Op-amp
Resistors Calculator of Non-Inverting Op-amp