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
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
Light Laser LED Circuits
Light Laser LED Circuits
Light Sensing Circuits
Light Dimmer Circuits
Flip-Flop Independent Lamp Driver
Assume first that SCR1 is on and SCR2 is off so that CI is fully charged, with its LMP2 end positive. The
This strobe gives a visual indication of a sensor input. The input signal causes Ul, a light dependent resistor, to chaijge CI
Flashing Led Controller
The LED with integrated flasher is connected in series with the base-emitter junction of transistor Tl. Thus, the l
Ac Circuit Led Power Indicator
Many electronic circuits need an indication that they are under power; for most ac circuits, a neon lamp is
Mains Failure Indicator
When the mains voltage is present at the input terminals, the transistor in the optocoupler is on, T1 is off, and s
Battery-operated equipment can work on one set of batteries for a long time nowadays. However, if it is left on inadvertently,
Ir Receiver I
This receiver is built around a uPC1373 IR remote-control preamplifier, a sensitive 30-to-40 kHz tuned detector, an automatic
Ir Receiver Ii
Q3 is an IR phototransistor that responds to a modulated IR beam. Q1 amplifies the ac component of the IR beam. Q2 drives a
Wireless Ir Security System
This system contains an IR transmitter, an IR receiver/RF transmitter, and an RF receiver/alert beeper. Two IR
Ir-Controlled Soldering Station
An IR-sensitive phototransistor is used to sense soldering-iron temperature. The phototransistor must see t
Simple Ir Transmitter
The IR diode"s flash rate is determined by the value of CI, a 220-Â¥ capacitor that sets the rate of oscillation at 1
Three-Way Touch Lamp
A three-way switch to control a lamp (off-dim-bright, etc.) uses an NE555 timer to generate a one-second pulse, trigge
This very special mains-operated dimmer for domestic or industrial lights is not available in proprietary form: it ena
Lamp II is a household lamp. When the switch is in the center position, the lamp is operated on half-wave rectified ac; the ef
Automatic Emergency Lighting Unit
This unit uses a Nicad battery to provide power to an emergency lighting setup. When power fails, T1 beco
3-Way Light Control
This hookup is useful in some house wiring situations, where only two wires are available between switches, rather than
"Automatic" Light Bulb Changer
The circuit presented here guarantees that if bulb Lai "gives up the ghost," bulb La2 will take over its tas
Scr Capacitor Turn-Off Circuit
After the SCR turns on, CI charges up to almost the full supply voltage via R3 and the anode of the SCR. Whe
Bias Supply For Microwave Preamps
These two circuits provide bias for the microwave preamps shown in this text. The circuit in Fig. 51-5(a)
This circuit uses readily available parts to implement a 0-to-200-nA current source. The circuit borrows a PMOS
Uhf Motion Detector
The UHF motion detector operates on the Doppler radar principle. Ql is an oscillator that creates a radiated signal. An
Laser Power Supply
ICl is a 555 timer running at about 16 kHz. This IC drives Ql, a TIP146, which produces a 12-V square wave across Tl pri
Strobe Alert System Circuit
The circuit is activated by an LED/photoresistor isolator (Ul), which is a combination of a light-dependent resistor (LDR) and an LED in a single package. That device was chosen because of its high isolation (2000 V) characteristic, which is necessary because the strobe part of the circuit is directly connected to the ac line.The voltage...
3 Channel Color Organ Circuit
The ac line power is brought back into the circuit through Fl, a protective 5-A fuse. One side of the ac line is connected to one side of each ac outlet. The other side of the ac line is connected to each SGR or silicon-controlled rectifier. Each SCR is, in turn, connected to the other side of each ac outlet.An audio signal is brought into the...
Super Led Flasher Circuit
The super LED flasher is actually two complete LED flasher circuits on one circuit board. The first, LED flasher is made up of 1C1 and LEDs D1 and D2. IC1 is a 555 timer IC configured as an astable (free-running) multivibrator with its output on pin 3. The frequency of the 555`s oscillation is controlled by R2, R3, and CI. Resistor R1 limits...
Led Christmas Tree Light Flasher Circuit
Three individual flashing circuits that use an LM3909 LED flasher/oscillator IC create the appearance of a pseudo-random firing order. The combination of CX!RV C.JRb, and C^R control the blink rate, which is between 0.3 and 0.8 s, and the inherent wide tolerance range [-20% to +80%) of standard electrolytic capacitors add to the irregularities...
Ir Pulse To Audio Converter Circuit
If your ear is good, you can use this IR-pulse-to-audio converter to troubleshoot infrared remote-controls. It is also a good project for detecting infrared-light sources. A photo cell module (Radio Shack P/N 276-137) detects IR radiation and drives audio IC Ul.
Ir-Controlled Remote A/B Switch Circuit
Useful for A/B control, the IR receiver shown controls a relay from an infrared beam that has a pulsed tone-modulated signal. Ql is the photo receptor feeding op amp IC1, tone decoder IC2, and flip-flop IC3.
Infrared Receiver Circuit
The circuit operates from a 5-V supply arid has a current consumption of 2 mA. The output is a current source that drives or suppresses a current of more than 75 with a voltage swing of 4.5 V. The Q-killer circuit eliminates distortion of the output pulses because of the decay of the tuned input circuit at high input voltages.
Wireless Ir Headphone Transmitter Circuit
The transmitter for the wireless headphones is built around a CD4046 CMOS phase-locked loop, coupled with a driver transistor, and a pair of infrared LEDs. Although the CD4046 is comprised of two phase comparators, a voltage-controlled oscillator (or VCO),
Infrared Remote-Control Tester Circuit
The infrared remote-control tester uses a sensitive PN-type solar sensor that is connected directly to a Darlington amplifier made up of transistors Q1 and Q2. Biasing is provided by R1 and PI, a variable resistor that serves as a sensitivity control. The collector lead of Q1 is the output lead of the Darlington amp, and it is connected to a...
Efficient Laser Supply Circuit
Driving Helium-Neon Lasers can be simplified considerably using This power-supply configuration. When power is applied, the laser doesn`t conduct and the voltage across the 190- resistor is zero. However, a resonant circuit and a voltage tripler then produces over 10 kV to turn on the laser.
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
CMOS Circuits Tutorial