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
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...
This circuit provides 20 Â±0.1 dB voltage gain from 0. 5 to 25 MHz and Â± 3 dB from 70 kHz to 55 MHz. An LM733 video amplifier furnishes a low input-noise spec, 10-I"V typical, measured over a 15.7-MHz bandwidth.
The operation of the unit revolves around three !Cs: a 4093 quad NAND Schmitt trigger, a 4066 quad analog switch, and a 7555 timer. When a high is fed to probe 1 in, it is inverted to IC1a and once again by IC1b, so that the input to IC2a is high. Thathigh causes the switch contacts in IC2a to close. With the contads closed, a high-level...
This circuit provides about 20 dB voltage gain with a frequency range from 0.5 to 50 MHz. You can extend tbe low-frequency response of this circuit by increasing tbe value of the 0.05-ILF capacitor- or try removing tbe capacitor. This circuit delivers a particularly small level of input noise, measured at approximately 20 p.V over a...
The circuit will provide a 20 Â±0.1 dB voltage gain from 500 kHz to 50 MHz. The low-frequency response of the amplifier can be extended by increasing the value of the 0.05-JLF capacitor connected in series with the input terminal. This circuit will yield an input-noise level of approximately 10 !LV over a 15.7-MHz bandwidth.
Oscilloscope triggered sweep circuit
The circuit"s input op amp triggers the timer, sets its flip-flop and cuts off its discharge transistor so that capacitor C can charge. When capacitor voltage reaches the timer"s control voltage of 0.33 Vee. the flip-flop resets and the transistor conducts, discharging the capacitor.
IC1a, IC1b, and IC1c of the quad two-input NAND gate 4011 are connected as an astable multivibrator; IC1d is connected as an inverter. Terminals 3 and 11 of the 4011 produce square waves with opposite phases. The square waves, eP, at the output of IC1a, passing through differentiator C4R13, then form positive and negative pulses, e,. The dual...
Two important properties of the 8043 are used to advantage in this circuit. The low input bias currents give rise to slow output decay rates (droop) in the hold mode, while the high slew rate at 6 V/p,s improves the tracking speed and the response time of the circuit. The upper waveform is the input 10 V/div, the lower waveform the output 5 V...
Feedback is the same as a conventional op-amp voltage follower which yields 11 unity-gain, noninverting output. This hookup also has a very high input impedance. The only difference between a track-and-hold and a sample-and-hold is the time period during which the switch is closed. In trackand- hold operation,
This circuit uses the speed and drive capability of the HA-5190 coupled with two high-speed DMOS FET switches. The input amplifier is allowed to operate at a gain of -5, although the overall circuit gain is unity.
Itis often required that a signal be filtered prior to sampling. This can be accomplished with only one device. Use any of the inverting and noninverting filters that can be built with op amps.
The sample-and-hold function has often been accomplished with separate analog switches and op amps. These designs always involve performance tradeoffs between acquisition time, charge injection, and droop rate. The HA-242-/2425 monolithic sample-and-hold.
The LM101A provides gain and buffers the input from storage capacitor C2. R2 adds a zero in the open loop response to compensate for the pole caused by the switch resistance and C2, improving the closed-loop stability. R1 provides a slight delay in the digital drive to pins 1 and 9. C1 provides cancellation of coupled charge, keeping the...
Channel 1 is wired as a voltage follower and is turned on during the track/sample time. Ifthe product of R x Cis sufficiently short compared to the period of maximum output frequency, or sample time; Cwill charge to the output level.
This illustrates another application in which the hookup versatility of a sample-and-hold often elimi nates the need for a separate op amp and a sampleand- hold module.
This tachometer lets you measure heartbeats, respiratory rates, and other low-frequency events that recur at intervals of 0.33 to 40.96 seconds. The circuit senses the period offm, computes the equivalent pulses per minute, and updates the LCD accordingly. Although the decimal readout equals 60 fm, the circuit doesn"t actually produce a...
A standard shaft encoder"s A and B ports generate square waves with the same frequency as the shaft turns. The phase of A will lead or lag that of B by 90Â°, ~depending on the direction of rotation. To obtain maximum resolution, the tachometer circuit must count every change of the state for the A and B signals. Each such change causes a...
If the tube is level with respect to gravity, the bubble resides in the tube"s center and the electrode resistances to common are identical. As the tube shifts away from level, the resistances increase and decrease proportionally. Transducers of this type must be excited with an ac waveform to avoid damage to the partially conductive liquid...
The 5-MHz track and hold shown here has a 400-kHz power bandwidth driving Â±10 V. A buffered input follower drives the hold capacitor, C4, through Ql, a low resistance FET switch. The positive hold conuuand is supplied by TTL logic, with Q3Ievel shifting to the switch driver, Q2. The output is buffered by A3. When the gate is driven to V-for...
When the switch is closed or the FET is conducting, the circuit behaves as an inverting amplifier with a gain of R2/Rl. Since as the inverting tenninal of the op amp is a virtual ground, the capacitor is kept charged to the output voltage by the op amp. When the switch is opened and the FET is nonconducting, the voltage at the output is held...
This circuit reads and stores voltages, tbus freezing the meter reading even after tbe probes are removed. The op amp is configured as a unitygain voltage follower, witb C1 situated at tbe input to store tbe voltage. For better performance, use an LF13741 or a TL081 op amp in place of tbe 741.
In a single difference amplifier configuration, the AM-427 exhibits excellent common-mode rejection and spot nois
An Intersil 7101 31/2-digit A/D converter is used to display the duty cycle of a pulse train as a percentage. The frequ
Four-Trace Oscilloscope Adapter
This simple adapter uses an oscillator (567) to drive a counter (U2) and switch (U3) that selects the outpu
Digital Tachometer Circuitry
This system can be used with 4-, 6-, or 8-cylinder automobiles. The timebase formed by IC5 is an oscillator th
This circuit develops an output voltage that is proportional to the magnetic induction, B, flowing through its probe"s coi
Simple Absolute Value Circuit
When an input voltage is positive, the output of ICA is negative and diode D does not conduct; hence the outp
This circuit measures capacitance by the time it takes an unknown capacitor to reach 6.32 V (10 V 63% or 1RC time const
Electrolytic Capacitor Reforming Circuit
Sometimes electrolytic capacitors that are stored for some time will exhibit high leakage currents
Capacitor Esr Measurer
The equivalent series resistance (ESR) of a capacitor can be measured using this circuit and an ac voltmeter. Ul fun
The circuit uses a synchronous-detection scheme to measure low-level resistances. Other low-resis-tance-measuring circui
Sensitive Continuity Checker
This continuity checker (built around an LM339 quad comparator with open-collector outputs) eliminates false 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