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
New Circuits Page 16
make 6v 4ah automatic battery charger
The battery charger circuit which is able to charge 6V 4. 5 AH lead acid batteries. The schematic is very simple and using only few components. IC LM317T is the heart of the circuit. The circuit is automatic so when the battery will become full charge it will stop charging. These type of circuits are very useful for solar garden light and can also
The idea is to create a system that allows the residents to play a movement based game similar to laser tag. Using GPS and a digital compass we track their localized movements and position vector. That information is used when the player wants to fire` upon another player. All the information communicated via WiFi to central server, which processe
interfacing rs 232 with spartan 6 fpga
The UART (universal asynchronous receiver/transmitter) is a serial protocol with separate transmits and receives lines, and can be used for full duplex communication. The Spartan-6 board has 2 Serial Port, indicated as in Figure. RS-232 serial communication is performed through a 9-pin SUB-D connector and the FPGA UART module. The UART is one of t
led display voltmeter in probe model circuit
radio wave alarm
This very simple alarm circuit is sure to have the police beating a path to your door - however, it has the added advantage of alerting you to their presence even before their footsteps fall on the doormat.
PS/2 Keyboard IR Receiver
A few years ago, someone gave me a small wireless infra-red keyboard, part no. RC-KB2, designed to be used with a Kenwood audio system. As soon as I saw it, I wanted to discover it`s transmission format. Why Because I would then be able to build a small receiver which would allow me to use this keyboard on a PC with a PS/2 port. Two years later,
solid state tesla coil
!This instructable is meant to give detailed instructions on building a solid state tesla coil based off of steve ward`s mini sstc schematic. Ok, here..
audio tone control with 2 transistor
The first BC109C transistor acts as a buffer. It provides the circuit with an input impedance of around 250 000 has a voltage gain of slightly less than unity. As Baxendall tone control circuit is a passive design, all audio frequencies are attenuated. The position of the controls and the ballast capacitor alters the audio response. The last trans
Softrock Lite II
The Local Oscillator stage implements a basic Colpitts Crystal Oscillator with a buffer stage to increase the signal level. The oscillator produces a signal that is at the crystal`s specified fundamental frequency. In reality, for each frequency the crystal circuit will oscillate at a slightly lower frequency (~ - 1 kHz), due to the capacitive div
2w switching power supply
high frequency waveform generator
This is the circuit of waveform generator. Waveform generator is very useful in electronic experiment and design. This circuit is generates sine wave oscillation, but actually we can modify the circuit to generate triangle or square wave function. This is the figure of the circuit. This circuit is based on MAXIM IC. This integrated circuit chip gi
Izzy Wizzy Audio
The aim was to build a MC sensitive preamp that was quiet, used only tubes and had a certain something that made you want to listen. This thing is quiet and if built properly, hum free. I have to put my head very near the speaker to hear a slight trace of hum or hiss at loud listening levels. The main design aim other than to make it sound good wa
low voltage monitor schematic
Low Voltage Monitor circuit is highly desirable for security and protection against everyday damage your equipment, especially for your favorite car. This circuit may be very simple / very simple to make because only by using ic LM339. The workings of this circuit is Buzzer will sound and lights Led will light up when your car battery in a state...
Tube Distortion Pedal circuit diagram
Tube Distortion Pedal circuit diagram. IC1 : 747 dual op-amp, other ICs may be substitued but pinout will different. You should check the datasheet. IC2 : LM340K-12V Voltage Regulator. All resistors are 1/2 W. Bridge Rectifier Full wave bridge recitifier, 50 Volts, 500 mA minimum The following circuit is Tube Distortion Pedal for guitar effect
The Colpitts oscillator
Figure shows the Colpitts oscillator circuit. It has a base frequency crystal, and the frequency is 1499 kHz, crystal SJT is connected to the both ends of capacitor C2, C3. Emitter divider resistor R2, R3 provide basic feedback signal, the feedback voltage is controlled by the capacitive dividers C2, C3. SJT crystal provides l499kHz sine wave...
Classic 8051 Memory Layout
The CODE and CONST memory classes are typically stored in ROM that may be either off-chip or on-chip. The CODE memory class is used for the actual program code while the CONST memory class is used for constant variables declared in code space. In addition, up to 32 code banks may be used for code banking applications. While these are technically l
remote controlled fan regulator
Using this circuit, you can change the speed of the fan from your couch or bed. Infrared receiver module TSOP1738 is used to receive the infrared signal t..
current controlled oscillator
This circuit was in EDN`s "design ideas" section in the March 5, 2007 issue. It`s a fairly simple circuit and an easy way to investigate how the inductance of a toroid (or any core) is changed by saturation, which in this case is caused by applying a current to a secondary winding. With this circuit, the oscillator frequency is a function of the co
Simple Light Sensor Alarm circuit with NE555
This circuit sent out an alarm when its LDR sensor is exposed to light by sun or lamp. A 555 astable multivibrator was used here which sent signal a tone of about 1kHz upon detecting light. The sensor when exposed by light completes the circuit and makes the 555 oscillate at about 1kHz with transistor to drive current. Sensitivity can be adjust wit
Power Supply Schematic
The power transformer has three secondaries: 720V at 120mA center-tapped for the plate and screen supplies, 6. 3V at 3. 5A for the tube filament and bias power supply, and 5V at 3A (not used). Since the 5V secondary is not used, a little more current than 120mA can safely be drawn from the high voltage secondary. The high voltage secondary feeds...
Programmable Unijunction Transistor (PUT) Flasher Circuit
This is simple circuit that illustrates the function of the programmable unijunction transistor. It may be quickly wired on a proto-board. PUT Flasher Spec..
EL84 Amp Baby Huey
This design is based upon an ECL86 Amp design posted by Yves quite some time ago. This design uses shunt feedback to reduce the output stage rp and thus better drive the limited primary inductance of cheaper output transformers. Regardless of that, the result is good enough that its worth using reasonable quality transformers and while the common
Voltage Regulator 12V 1.5A for Battery by MC34063
The circuit is a good battery. It is Control Volttage regulator Output 12V 1.5A , Input Voltage battery 5V-13V Only. Use IC- MC34063 so easy circuit,..
light activated police siren using 555 timer
Here`s a simple light activated police siren using light dependent resistor and NE555 timer. Before you make this project, I would recommend you to make the following projects. The 555 timer with R1=68K(say timer1) is configured in slow astable mode and the timer with R4=10K(say timer2) is configured in fast astable mode. By applying voltage to t
Enhanced 5 Digit Alarm Keypad
This switch will suit the Modular Burglar Alarm circuit. However, it also has other applications. The Keypad must be the kind with a common terminal and a separate connection for each key. On a 12-key pad, look for 13 terminals. The matrix type with 7 terminals will NOT do. Choose the five keys you want as your code, and connect them to `A, B, C,
simple microphone circuit
I want to make a simple circuit with a microphone that just takes your voice and sends it to a speaker. I just want to understand how to hook up a mic..
1.2GHz Voltage Controlled Oscillator With Linear Modulation
Since high frequency voltage-controlled oscillators, or VCOs, are not easy to construct, Maxim ( has produced an integrated 1. 2GHz oscillator, the MAX2754. The center frequency is set using the TUNE input, and a linear modulation input allows the frequency to be modulated. The IC is available in an 8-pin µMAX package, operates from a supply of be
the design of the radar for back running vehicle of MSP430
It is developed that the ones that assist driving system intelligent improvement and car electronic system that demand to the car as people are networked, new radar for back running vehicle should can serial range finding and reveals the distance of obstacle, and have communication functions, can send the data to the bus line of car. The past...
MAX2385 MAX2385 MAX2386 CDMA + GPS LNA/Mixers
The MAXQ7667 smart system-on-a-chip (SoC) provides a time-of-flight ultrasonic distance-measuring solution. The device is optimized for applications involving large distance measurement with weak input signals or multiple target identification. The MAXQ7667 features high signal-to-noise ratio achieved by combining flexible electronics with the int
Low Cost Battery Condition Indicator
This design combines power-on and low-battery indication, can operate with any battery voltage up to 15V, has very low current drain (2mA or less) and costs less than $3. 50 with new parts. When the battery voltage is above a predetermined minimum, power on is indicated by what appears to be a steadily lit LED. In fact, the LED is being pulsed by a
TDS9092 TDS971 IEEE-488/RS232C
This is a Eurocard communications board for TDS2020F or TDS9092 computers (or earlier types). It contains an IEEE-488 Talker/Listener interface and two RS232 ports with all baud rates from 75 to 38400. A DIP switch on the board selects the IEEE address. The board comes complete with 45cm ribbon cable terminated in an IEEE-488 specification socket
telephone number display circuit diagram
The given circuit, when connected in parallel to a telephone, dis- plays the number dialled from the telephone set using the DTMF mode. This circuit can also show the number dialled from the phone of the called party. This is particularly helpful for receiving any number over the phone lines. The DTMF signal generated by the phone on dialling a nu
serial communication on atmega3216
A very basic introduction to RS232 based serial communication on ATmega32/16 using the USART hardware. But before you start reading, let me warn you this post is a bit lengthy (but contains everything you need as a beginner. so no skipping :P), so bear with it. Secondly, please keep a datasheet of ATmega32 ready with you, this is the link. I...
12V simple CFL driver
analog mv switch for digital meters
This circuit uses a 4052 as a DC Analog Multiplexer, the inputs to this Mux must be from Low Impedance Output OpAmps. The Resistors Shown are not needed once the Signal Conditioning Opamps are connected. The Restors can be 100K to keep the inputs from floating, that will not load an opamp. The resistors can attenuate signals if sensors are directl
LINEAR RAMP GENERATOR
The linear charging ramp is most useful where linear control of voltage is required.Some possible applications are a long period voltage controlled timer, a voltage to pulse width converter, or a linear pulse width modulator. Q1 is the current source transistor, supplying constant current to the timing capacitor Ct. When the timer is triggered,...
555 timer music instrument
A very simple music instrument/keyboard for playing music using a 555 timer chip circuit, a piece of paper and a pencil. To see it in action watch the how-to-make video below. And then I made the much fancier automatic music player in the photo below by making a playing head and a way to feed in a long sheet of paper with the musical notes...
Use an LED Matrix Horizontally
LEDs provide a convenient way to electronically display information. Although the seven-segment LED display, arranged in the form of the digit 8, is commo..
Inexpensive buffer circuit suitable for using to mix passive pickups with EMG active pickups, or buffering piezo pickups to mix with magnetics. Frequency response is pretty much flat, and noise is fairly comparable to passive pickups if built correctly. The circuit will easily drive a load of 10K or lower, so even long cable runs shouldn`t be an...
Sound-Activated Lamp circuit diagram (Relay/Switch)
This simple circuit shown int the schematic diagram actives the switch using sound. We can use this circuit for various applications, such as automatic (sound-controlled) disco light or car s LED light show. The Q1 amplify the audio from mic. The R1 is used to adjust the peak of signal to greater than about 0.7 volts, act as sensitivity...
Parametric EQ based bass boost circuit
So I needed a circuit to act as a bass boost. I ended up adapting this circuit (by ESP Sound) by excluding everything but the 35-150hz part. This..
FM Listening Bug Kit
As you can see in the schematic below this is a very simple circuit and will be an easy build. On thing the Schematic doesn`t convey very well is wher..
8051 Development System Circuit Board 3
This schematic is provided in the hope that it will be useful, but without any warranty, not even a warranty of merchantability or fitness for a particular purpose. The address bus in this schematic is connected in an unusual way, which is optimized for simpler point-to-point wiring and board layout. For anyone building the board using wire-wrap o
Homemade 20W fluorescent lamp dimmer circuit diagram
Homemade 20W fluorescent lamp dimmer Using the method of connecting capacitor in series can easily control the brightness of fluorescent lamps. To adapt to different lighting requirements. Figure 28 is a modified circuit diagram. When the switch connects to the 1, the brightness of the lamp is normal, the actual power is 20w; and connects to 2,...
OverUnity Lead Acid Battery Switching Self Battery Charging
The only way to know how fast a particular battery can recharge itself is to put it under load, vary the switching frequencies, on / off times, & then plot the results. A circuit drawing 0. 5 Amps at 12 Volts will charge a battery slowly, so increasing the power used to 2 amps or more is something you should be looking at if you want a fast charger
REMOTE CONTROL ANALYZER
A schematic diagram for the remote analyzer is shown. The circuit is powered from a simple 5-V supply, consisting of PL1, 51, T1, abridge rectifier (comprised of Dl through D4), capacitor C1, and a common 5-V regulator, UI. Switch 51 is the on/off control and is optional. The power-supply trans-former used in the prototype is a 12. 6-Vac unit, but
Reaction Capability TesterCircuit
Reaction Capability Tester is used to test and train man s quick-response capability. It has various type of construction and the Reaction Capability Tester as shown in the picture is composed of decimal counter CD4017 and luminous diode. The construction of Reaction Capability Tester is simple and can be used as a plaything to train and test...
cell phone operated land rover
VU Level Meters STEREO
Programmable Stiffness Joint
The "Programmable Stiffness Joint" is a device which is able to internally modify the rotational stiffness of a simple pivot joint. It is intended to serve as a proof-of-concept for future work in developing a model for determining the respective damping and stiffness components of the human ankle joint over the able-bodied gait cycle. This inform
TDA2030AL-TA5-T 18W Hi-Fi Audio Power Amplifier And 35W Driver
The TDA2549 is a complete i. f. circuit with a. f. c. , a. g. c. , demodulation and Video preamplification facilities for multistandard Television receivers. It is capable of handling positively and negatively modulated Video signals in both colour and black/white receivers.
Long Delay TimerCircuit
This timer was designed mainly to switch off a portable radio after some time: in this way, one can fall asleep on the sand or on a hammock, resting assured that the receiver will switch off automatically after some time, saving battery costs. R1 and C1 provide a very long time constant. When P2 is momentarily closed, C1 discharges and the near ze
Car battery charger Automative car and motorcycle schematics
The circuit was meant to be powered by a power supply, which is why there is no transformer, rectifier, or filter capacitors on the schematic. There is no reason why you cannot add these. To use the circuit, hook it up to a power supply/plug it in. Then, connect the battery to be charged to the output terminals. All you have to do now is push S1 (
phone hold circuit
Although a hold feature is standard on most new phones, a lot of us still use the origional bell phones. Those of us that require a hold feature will find this circuit very useful. It is easy to build, and is compact enough to be installed inside the phone with no real problem. It is also powered by the phone line itself, eliminating the need for
Temporary LED Lamp/Illuminator
This temporary lamp circuit is very helpful in emergency situation or in any application where we don`t have much time to turn off the lamp. Just press the..
Free Energy Schematic
The basic concept as I understand it, is a high frequency high voltage low current rectified and then used to charge a bank of high value capacitors and then to discharge them in pulse mode for brief period of time, nano seconds in fact by, means of a high speed electronic switching circuit or mechanical device and a rectification method that will
Digital sine wave generator
By using the reverse binary counter and the binary-coded decimal decoder can obtained the step voltage, and by approximating this voltage can be produced the sine wave signal with sufficient accuracy, suitable for many purposes. In the circuit diagram of the digital generator (see figure 1) the resistors R1. R9 is used to produce the first quarter
Electronic Dice Circuit
With this electronic dice the result is displayed with LEDs that are placed so every dice face is shown. In the circuit diagram, IC 4022 is used to count t..
Lexus RX300 330 3 2000 06 Wiring Diagram
Automatic Ni-Cd Battery ChargerCircuit
Automatic Ni-Cd Battery Charger circuit is shown in the above picture. The internal comparator of NE555 is set as 4.7V by Zener diode. If the potential of pin 6 becomes higher than this value, the output of pin 3 become lower; if the potential of pin 2 is lower than half of the reference voltage, the output voltage becomes higher,. When the...
Mosfet Amplifier 20Watt Output Power Schematic Diagram
This audio amplifier showed in this circuit diagram, is a very simple and efficiency audio amplifier circuit based on the TDA1308 integrated class-AB stereo headphone. The device is fabricated in a 1 mm Complementary Metal Oxide Semiconductor (CMOS) process and has been primarily developed for portable digital audio applications. You can use thi
Audio AmplifierCircuit - 30 Watts
I`m a bit of a newbie, but I love to experiment. I thought I would try to make a small guitar amplifier using some of the circuit designs posted here. I`m thinking of using this 30 Watt design (actually, the single 12VDC version mentioned in the comments below), but feed it with a preamp ( ) to be able to adjust input gain and have some tone cont
The camera and shutter control are completely self contained and can be used in any situation where you would like to take a number of photos automatically at a set interval in time. In this case it is for Kite Aerial Photography, but I have used this camera with an RC plane as well. I am sure you will come up with many more interesting applicatio
A deviation monitor can be made by connecting some form of frequency modulation (FM) detector to an AC voltmeter and calibrating the meter in units of frequency deviation. One method of detecting or demodulating the FM signal is to use a phase locked loop (PLL). A voltage controlled oscillator (VCO) is locked to the FM signal frequency by comparin
t230 direct interfacing microcontroller
MIDI Drum Machine Schematic MIDI Interface
Descriptions of the various modules in a home built music synthesizer - Sub-oscillator project. ..
LM3915 audio power level meter circuit design electronic project
using the LM3915 monolithic integrated circuit can be designed a very simple audio power level meter that senses analog voltage levels and drives ten LEDs, LCDs or vacuum fluorescent displays, providing a logarithmic 3 dB/step analog display. One pin of the LM39145 changes the display from a bar graph to a moving dot display. LED current drive is
single-813 crystal oscillator transmitter
Here is the single- 813 crystal oscillator transmitter, designed by RCA and exhibited in their advertisement on the back page of a "QST" magazine in 1938, and published by RCA in their HamTips bulletin, vol. 1, no. 4, dated December 1938. This transmitter`s output is 150 watts of CW or 100 watts of plate-modulated AM telephony. It seems obvious
Bidirectional motor control
One of the simplest ways to get a motor to turn in both directions is by using a double-pole, double-throw (DPDT) relay. Along with the relay, this hookup requires two transistors and two Stamp pins, one for on/off control and the other for direction control. The diagram below contains the schematic for this setup. The DPDT relay is switching...
Voltage Controlled Voltage Source
The disadvantage of the circuit above is that the supply of the op-amp is tied to the HV supply. Most op-amps are limited to around 30V on the supply, so the circuit wont work for higher output voltages. The circuit below avoids this this problem by inserting a n-channel mosfet, which can be fully controlled within the range of the op-amps power s
LED based transistor tester
Here is the circuit of a very simple transistor tester which used two LEDs for displaying the condition of a transistor. Both PNP as well as NPN transistors can be tested using this circuit. Quad 2 input CMOS NAND gate IC CD4011B is the heart of the circuit. Out of the four NAND gates inside the IC, only three are used here and they are used as NO
Implement automatic voltage switching into the SATL
CRTGND is not the same as GND, CRTGND connects to the mostfet drain/schottky diode. There is a downside to this circuit which is that there is a voltage drop when running from the USB side due to the diode. The USB voltage can vary between 4. 75V to 5. 25V and the good news is that our ATtiny85 can run fine at 16. 5MHz whilst at 4. 0V. If the...
iphone battery pack
How to create a Battery pack for your Apple device that is powered by normal Alkaline batteries. This will be a general overview of building the circuit for the battery pack and the detailed instructions for the case will be given in part 2 of this post. NOTE: When soldering the USB socket, face the open part to the right with the connector pins...
Touch switch using CD4011
A simple touch switch circuit using CD4011 is given here. The IC CD4011 is wires as a flip flop here. The 9, 13 pins of the IC works as the set and reset contacts respectively. CMOS ICs like 4011 require requires a very low current for controlling its gates. Since the pins 9 and 13 are connected to the positive via resistors R1 and R2, the logic ga
Microcontroller-based automatic night light circuit
While discussing an all-linear automatic night light circuit I mentioned that I was testing an MCU-based ANLC. Well, I`ve been tweaking the firmware since. The other day I installed the sensor outdoors and have connected the circuit to control 220VAC loads. Last night the circuit got fooled when clouds moved in at around 2am and reflected sufficie