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One LED display flashing volt

This circuit is LED display flashing with one LED. By when you press Switch S1 give wasp the circuit then to liberate. It as a result make LED1 bright about 0.5 second. By this circuit uses the integrated circuit of NS number LM3909. It is build the mono stable multi vibrator circuit produce low frequency. It uses low power supply 3V only just


Temperature - Light Brightness Meter with LCD

Circuit measures the temperature and ambient brightness of the surrounding environment at the location it is placed. The data from the ADC is the calculated and displayed on the LCD. The main CPU unit on board the device is the PIC16F873.


0-99 Two Digit Counter By IC 74LS48 , 74LS90

This is circuit 0-99 Two Digital Counter.

use IC TTL Digital IC 74LS48 x 2 to LED 7 segment Display,

and 74LS90 x 2 for Decade and Binary Counters.

Input Clock pin 14 from IC 74LS90.

Here is circuit use power supply 5V.


3 Digits Digital Volt Meter with PIC16F676

This is simple 3-digits digital volt meter.PIC16F676 used to read analog signal(voltage) and display the value on 3-digits 7-segment. You can apply similar principles to measure DC current with parallel R shunt.


The Car Voltage Gauge

The Car Voltage Gauge is based on 3 parts. The input circuit is an Analog to Digital Converter (IC2 CA3162E). The purpose of this chip is to sample an analog voltage and convert it to a decimal value which is read by a Display/Decoder Driver (IC1 CA3161E). This chip will turn each seven segment display on through the driver transistor Q1 - Q3. The power is derived from the car and is converted to 5 volts by the 5 volt regulator. The circuit works as follows: The 10uf capacitor is charged up by the cars voltage. Its value is then read by IC2 and a decimal value of that voltage is provided to IC1 which multiplexes the three display units. Each display is turned on sequentially with its appropriate value displayed. The transistors Q1 through Q3 control the drive to each seven segment display. By monitoring the cars voltage with an accurate multimeter you can adjust the "Zero Adj." pot and the "Gain Adj." pot for accurate readings. LED 1 and 2 are optional. They can be used to indicate power on or can light up a cut out display that says "Volts". This can be made by a plastic module that has a thin plastic cover on it with the word "Volts" cut into it. The LED's would be mounted inside the module.


Digital Step-Km Counter with IC 4026,4024

Max. range: 9,950 meters with two digits
Slip it in pants’ pocket for walking and jogging


R1,R3____22K 1/4W Resistor
R2________2M2 1/4W Resistor
R4________1M 1/4W Resistor
R5,R7,R8__4K7 1/4W Resistor
R6_______47R 1/4W Resistor
R9________1K 1/4W Resistor

C1_______47nF 63V Polyester Capacitor
C2______100nF 63V Polyester Capacitor
C3_______10nF 63V Polyester Capacitor
C4_______10µF 25V Electrolytic Capacitor

D1_______Common-cathode 7-segment LED mini-display (Hundreds meters)
D2_______Common-cathode 7-segment LED mini-display (Kilometers)

IC1______4093 Quad 2 input Schmitt NAND Gate IC
IC2______4024 7 stage ripple counter IC
IC3,IC4__4026 Decade counter with decoded 7-segment display outputs IC

Q1,Q2___BC327 45V 800mA PNP Transistors

P1_______SPST Pushbutton (Reset)
P2_______SPST Pushbutton (Display)

SW1______SPST Mercury Switch, called also Tilt Switch
SW2______SPST Slider Switch (Sound on-off)
SW3______SPST Slider Switch (Power on-off)

BZ_______Piezo sounder

B1_______3V Battery (2 AA 1.5V Cells in series)

This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants’ pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is always on to separate Km. from hm. The rightmost display D1 (the least significant digit) shows hundreds meters and its dot illuminates after every 50 meters of walking. A beeper (excludable), signals each count unit, occurring every two steps.
A normal step was calculated to span around 78 centimeters, thus the LED signaling 50 meters illuminates after 64 steps (or 32 operations of the mercury switch), the display indicates 100 meters after 128 steps and so on. For low battery consumption the display illuminates only on request, pushing on P2. Accidental reset of the counters is avoided because to reset the circuit both pushbuttons must be operated together.
Obviously, this is not a precision meter, but its approximation degree was found good for this kind of device. In any case, the most critical thing to do is the correct placement of the mercury switch inside of the box and the setting of its sloping degree.


This be delay timer circuit model to be simple. It be the character delays to close electric all appliances. By fix the time about 5 minute. It can fine decorate the time. When see the circuit uses digital IC number CD4093 make good easy. And use transistor driver relay. It performs to edit the electricity gives with load or the electric appliances is all. When see our circuit uses electronic part that seek easy. May have no the problem about part. For LED1 use for display when feed power supply reach the circuit. It usability easily just press S1 for begin be usable. more...


Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I would strongly suggest a Tantalum Bead type. Switch 3 adds an extra resistor in series to the timing chain with each rotation, the timing period us defined as :-

Timing = 1.1 C1 x R1

Note that R1 has a value of 8.2M with S3 at position "a" and 49.2M at position "f". This equates to just short of 300 seconds for each position of S3. C1 and R1 through R6 may be changed for different timing periods. The output current from Pin 3 of the timer, is amplified by Q1 and used to drive a relay.

Parts List:
Relay 9 volt coil with c/o contact (1)
S1: On/Off (1)
S2: Start (1)
S3: Range (1)
IC1: 7555 (1)
B1: 9V (1)
C1: 33uF CAP (1)
Q1: BC109C NPN (1)
D1: 1N4004 DIODE (1)
C2: 100n CAP (1)
R6,R5,R4,R3,R2,R1: 8.2M RESISTOR (6)
R8: 100k RESISTOR (1)
R7: 4.7k RESISTOR (1) more...

Ultra-Long Time Delay By IC Timer 555
This be the circuit delays to have for a long time. By use the integrated circuit Timer 555 or Ultra-Long Time Delay By IC Timer 555 by R2 use for fine the frequency of pulse from the integrated circuit NE555 bring divide by wasp with 4017 each 10 in the end the time delays to follow want. Part S1 for choose Reset or Run of the circuit. more...

Circuit 0-99 counter by IC 4017×2
When you want the counter circuit since 0 arrive at 99. I thinks this circuit may on the same wave length you certainly. it uses IC 4017 decade counter/divider follow circuit picture. When feed a signal clock at 14 pin cause the position logic at a pin output. From 0 to 99 for switch S1 perform choose RUN or Reset. Please see circuit picture will understand increasingly. Almost forget integrated number this circuit, want the fire feeds 3V low arrive at 15V because be IC digital CMOS there. more...

All IC�s are CMOS devices so that a 9V PP3 battery can be used, and the current drawn is very low so that it will last as long as possible.

The circuit comprises of �

1 555 timer IC4.
1 4027 flip flop IC1.
2 4017 Decade Counter IC2 and IC3.
3 4071 OR gate IC5, IC6 and IC7.
1 470 Ohm resistor 1/4 watt R3.
2 10K resistors 1/4 watt R1 and R2.
1 6.8UF Capasitor 16V C1.
9 Super brght LED�s 1 to 9.
1 9V PP3 Battery.
1 single pole switch SW1.
1 Box.

How The Circuit Works.

IC4, C1, R1 and R2 are used for the clock pulse which is fed to both the counters IC2 and IC3 Pin 14.

IC1 is a Flip Flop and is used as a switch to enable ether IC2 or IC3 at pin 13.

IC7a detects when ether IC2 or IC3 has reached Q9 of the counter pin 11.

IC5, IC6 and IC7a protects the outputs of the counters IC2 and IC3 using OR gates which is then fed to the Anodes of the
LED�s 1 to 9. more...

This is a 4 digit decimal counter which can operate as a free running counter or in count and hold mode with manual reset. In either mode the counter can be preset to count to a specified value. Clock edge and leading zero suppression can also be configured. The 7-segment display and indicator LEDs are multiplexed. It will drive most common anode 7 segment LEDs. I used four single digit LEDs but a four digit LED module could also be used. In free running mode the overflow output resets on the next clock pulse. Therefore the pulse duration is directly related to the input clock frequency. more...

This project provides an simple F1 motor racing style 5 light race start sequence with a random delay that you can use on a real race track, kart circuit or even your slot-car circuit. Operation is simple; when the start button is pressed all the LED clusters are off. They then illuminate sequentially at one second intervals until all five LED clusters are on. After a random interval between 1 and about 7 seconds the LEDs extinguish, signalling the start of the race. Once the LEDs have extinguished simply press the start button again to initiate another race start sequence. more...

This 1 channel infrared transmitter/receiver remote control is the cheapest and simplest you can find. The transmitter transmits a sequence of pulses on 36 KHz frequency carrier. The diodes are Schottky type because of their low voltage drop (only 0.2V). more...

A triac controller for switching resistive loads directly from the mains supply using the zero crossing technique. The device is powered directly from the mains via a diode and dropper resistor, and the IC has its own regulator to limit its supply to 9.25V. To ensure that no switching occurs outside of the zero crossing point, full wave logic is employed to guarantee that complete mains cycles only are switched to the load more...

If friends seek touch switch Circuit model to be simple. I begs for to advise this circuit, use integrated digital circuit number IC 4011 perform be Schmitt Trigger , and the integrated circuit IC 4020 perform be two divider circuit. It is control electric appliances work with Relay by when we touch at the sensor point for the first time On,when press for the second time will Off Relay. For other equipment nothing is a lot of request friends , see in the circuit better. more...

This circuit is the sound controls automatic circuit, by it will fix to don’t give popularity level in the sound doesn’t expire. When feed sound signal reaches in this circuit , as a result , will have a signal, will the power goes up to flow through LED shine to LDR. The connection and a resister have a side input ,make control popularity level in the sound that a side output get , when see the circuit has already. I uses important equipment , be the transistor number BC109 and other equipment a little again. By you can fix signal sound level can control with VR1 with try fine can decorate follow want. more...

The switching power supply provides 12 volts, at 10 amps, maximum, using a discrete transistor regulator with an op-amp functioning as a comparator in the feedback circuit.

With reference to the schematic, the front panel power-on light is not shown. There is no adjustable current limiter in this unit, although R1, R2, R3, Q2, R8, R9, C5 and Q4 set the current limit to approximately 10 amps. As you can see, the design is very similar to that of a linear power supply, except that L1, and D1 have been added, and U1 operates in a switching mode as a comparator with a small amount of hystersis. The switching frequency of this unit varies with the output current drawn by the load. This is an undesireable feature, which is why PWM regulators are used today. With a PWM regulator, the switching frequency is constant and will produce spurs only at known discrete frequencies rather than spurs at all frequencies. The Darlington-connected pass transistor block in the schematic is there twice (in parallel) for robustness. R4 in an internal trim-pot that can set the output voltage anywhere between 5 to 15 volts. more...

Any �button� of any remote control may be used to work this universal switch. The button must be pressed for about one and a half seconds (determined by R3 and C2) before the relay will operate. The circuit will remain in this state (latched) until reset. To reset, any button is pressed on the remote handset and held for a short duration.
For example, if you were watching TV, you could press and hold any button on the TV remote to trigger the circuit. In order not to change channel, you could press the button of the channel you are watching. You can connect anything to the relay, for example a lamp, but make sure that the relay contacts can handle the rated voltage and current.

Circuit Operation:
IC1 is an Infra Red module. IR modulated pulses are received and buffered by this IC. It has a standard TTL output, the output with no signal is held high by R1. One gate of a CMOS inverter drives LED1 as a visible switching aid. Another gate buffers the signal and applies it to the time constant circuit, comprising R3,C2,R4 and D1. C2 charges via R3, and discharges via R4, D1 prevents quick discharge via the low output impedance of the CMOS buffer. The time taken to charge a capacitor is the product of resistance and capacitance, more commonly known as the RC time constant. At one RC a capacitor will only charge to 63% of the supply voltage. It takes 5 RC�s for a capacitor to reach 99% charge. In this circuit the capacitor charge has to reach the logic threshold of the CMOS invertor. As the power supply is 5 Volts, the input threshold is around 3.6V, which takes about 3RC�s or about 1.5 seconds. Once reached the inventor triggers the 555 timer and operates the flip flop. A simulation of received pulses, filtering and output pulse is shown below. Note that this is not from the actual circuit ( in which case the reconstructed pulse would be high for the duration of the 555 monostable) but only a spice simulation.

The pulses are further buffered and contain �jaggered edges� as shown above. These edges are produced by the modulated IR data, and have to be removed. This is achieved using a 555 timer wired as a monostable, IC3, having an output pulse duration R5, C4. A clean output pulse is produced to activate the bistable latch, IC4. This is a D type flip flop, built with a TTL 7474 series IC and configured as a bistable. Any version of the 7474 may be used, i.e. schottky 74LS74, high speed 74HCT74 etc. The input is applied to the clock pin, the inverted output fed back to the data input and clear and preset lines are tied to ground. For every pulse the relay will operate and latch, the next pulse will turn off the relay and so on. Note that quick turn on and off of the relay is not possible. The output pulse is set at about 2.4 seconds. and input delay by R3, C2 set about 1.5 seconds.

Parts List:
R1 3k3
R2 1k
R3 22k
R4 220k
R5 1M
R6 3k3
B1 12 V
D1 1N4148
D2 1N4003
Q1 B109
IC1 IR1 available from Harrison Electronics or TSOP1838 or similar
IC2 4049
IC3 CA555
IC4 SN74HCT74 or SN74LS74
IC5 LM7805
Relay 12 Volt coil with changeover contact
C1 100u
C2 22u
C3 100n
C4 2u2 more...

Although designed to work at 12-volts - this alarm is easily adapted for a 6-volt system. So it will protect your "Classic Bike". And because the standby current is zero - it won't drain your battery. The circuit features a timed output and automatic reset. It can be operated manually using a key-switch or a hidden switch. But - if you add an external relay - it will set itself automatically every time you turn-off the ignition. 

Schematic Diagram 

Any number of normally-open switches may be used. Fit the mercury switches so that they close when the steering is moved - or when the bike is lifted off its side-stand - or pushed forward off its centre-stand. Use micro-switches to protect removable panels and the lids of panniers etc. 

While at least one switch remains closed - the siren will sound. About two minutes after the switches have been opened again - the alarm will reset. How long it takes to switch off depends on the characteristics of the actual components used. But - up to a point - you can adjust the time to suit your requirements by changing the value of C1 

Fit the 1-amp in-line fuse as close as possible to your power source. This is VERY IMPORTANT. The fuse is there to protect the wiring - not the circuit board. Both the board and switches must be protected from the elements. Dampness or condensation will cause malfunction. Without the terminal blocks - the board is small. Ideally, you should try to find a siren with enough spare space inside to accommodate it. 

Instead of using a key-switch you can use a hidden switch - or you could use the normally-closed contacts of a small relay. Wire the relay coil so that it's energized while the ignition is on. Then - every time you turn the ignition off - the alarm will set itself. 

When it's not sounding - the circuit uses virtually no current. This should make it useful in other circumstances. For example, powered by dry batteries - and with the relay and siren voltages to suit - it could be fitted inside a computer or anything else that's in danger of being picked up and carried away. The low standby current and automatic reset means that for this sort of application an external on/off switch may not be necessary. 

The Support Material for this circuit includes a step-by-step guide to the construction of the circuit board, a parts list, a detailed circuit description and more. more...

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