Circuit electrinic: circuit

Showing posts with label circuit. Show all posts

Showing posts with label circuit. Show all posts

Friday, January 10, 2014

555 IC Timed Beeper Circuit Diagram

This is a simple timed beeper circuit diagram of beeper using 555 timer. This circuit can be employed to energize lights, horn, or other signaling device at any desired interval when the mercury switch is triggered. Since the current handling capability of mercury switch is not so high, an SCR is used to handle current drawn by the 555 timer circuit. Chose the SCR current rating of 500mA at minimum to safely drive the 555 IC and the relay. The relay is not needed when the current drawn by alarm is less than 200mA, in this case the alarm can be installed to directly replace the relay coil. Here is the schematic diagram of the circuit.

555-IC Timed Beeper Circuit Diagram

555-IC Timed Beeper Circuit Diagram

Thursday, January 9, 2014

Over voltage Protection Circuit Diagram

This is a Over voltage Protection Circuit Diagram. A silicon-controlled rectifier is installed in parallel with the 12-V line and connected to a normally-closed 12-V relay, K1. The SCRs gate circuit is used to sample the applied voltage. As long as the applied voltage stays below a given value, SCR1 remains off and Kls contacts remain closed, thereby supplying power to the load.

When the source voltage rises above 12 V, sufficient current is applied to the gate of SCR1 to trigger it into conduction. The trigger point of SCR1 is dependent on the setting of R1. Once SCR1 is triggered (activating the relay), K1s contacts open, halting current flow to the load.

Over voltage Protection Circuit Diagram

Over voltage Protection Circuit Diagram

Friday, December 27, 2013

Under voltage Indicator for Battery Equipment Circuit Diagram

This is the simple Under voltage Indicator for Battery Equipment Circuit Diagram. Due to the low duty cycle of flashing LED, the average current drain is 1 mA or less. The NE555 will trigger the LED on when the monitored voltage falls to 12 volts.The ratio of Rl to R2 only needs to he changed if it is desired to change the voltage point at which the LED is triggered.

Under voltage Indicator for Battery Equipment Circuit Diagram

Under voltage Indicator for Battery Equipment Circuit Diagram

Friday, December 20, 2013

Build a Bridge Circuit Diagram With One Power Supply

This is simple Bridge Circuit Diagram With One Power Supply. For systems with only one power supply, two op amps act as instrumentation and buffer amps. The OPA111 AM buffers the reference mode of the bridge and applies that voltage to the instrumentation amps ref terminal. Output is taken between the amplifier outputs to exclude the fixed output offset.

The additional op amp creates a bridge error of 2, where IB=bias current of op amp and R is the resistance of one leg of the bridge.

Bridge Circuit Diagram With One Power Supply

Build a Bridge Circuit Diagram With One Power Supply

Wednesday, December 18, 2013

Simple Knight Rider lights Circuit for model cars

This simple circuit drives 6 LEDs in Knight Rider scanner mode. Power consumption depends mainly on the type of LEDs used if you use a 7555 (555 CMOS version).

Simple Knight Rider lights Circuit

Simple Knight Rider lights Circuit for model cars

Note
That V_DD and GND for the ICs are not shown in the circuit drawing.

Pin-outs:
(7)555		4017
1	GND	1	Q5	9	Q8
2	TRIGGER	2	Q1	10	Q4
3	OUTPUT	3	Q0	11	Q9
4	RESET	4	Q2	12	CO
5	CONTROL VOLTAGE	5	Q6	13	NOT ENABLE
6	THRESHOLD	6	Q7	14	CLK
7	DISCHARGE	7	Q3	15	RESET
8	V_DD	8	GND	16	V_DD

Tuesday, October 8, 2013

POWER CONVERTER TOPOLOGY ELECTRONIC CIRCUIT DIAGRAM

POWER CONVERTER TOPOLOGY and MOSFET SELECTION FOR 48-V TELECOM APLICATIONS ELECTRONIC CIRCUIT DIAGRAM

Output voltages are frequently 5V and below with 3.3V probably the most common requirement, and 2.5V gaining in popularity. If a processor is on the card, voltages as low as 1.3V are not unlikely. One common approach is to regulate a distributed power bus, say the 5V rail, and then use non-isolated DC/DC converters to generate lower voltages. With the tendency away from 5V, the 3.3V rail is beginning to serve as the distributed bus, although, from the power supply designer’s perspective, this is not the most of desirable situations.

Fairchild has recently introduced a family of high voltage MOSFETs ranging from 80- to 200-V drain voltage specifications. This application note will provide information helpful in the proper selection of FETs for primary side switches – available in various types of 48V power converters.

Saturday, October 5, 2013

9 Volt 2 Amp PSU Circuit

A simple 9 Volt 2 amp supply using a single IC regulator.

The circuit will work without the extra components, but for reverse polarity protection a 1N5400 diode is provided at the input, extra smoothing being provided by C1. The output stage includes C2 for extra filtering, if powering a logic circuit than a 100nF capacitor is also desirable to remove any high frequency switching noise.

Circuit diagram:

9 Volt 2 Amp PSU Circuit Diagram

Notes:

There is little to be said about this circuit. All the work is done by the regulator. The 78S09 can deliver up to 2 amps continuous output whilst maintaining a low noise and very well regulated supply.

Author : Andy Collinson Copyright : zen22142

Monday, September 23, 2013

Automatic Heat Detector Circuit

This circuit uses a complementary pair comprising NPN metallic transistor T1 (BC109) and pnp germanium transistor T2 (AC188) to detect heat (due to outbreak of fire, etc) in the vicinity and energise a siren. The collector of transistor T1 is connected to the base of transistor T2, while the collector of transistor T2 is connected to relay RL1.

The second part of the circuit comprises popular IC UM3561 (a siren and machine-gun sound generator IC), which can produce the sound of a fire-brigade siren. Pin numbers 5 and 6 of the IC are connected to the +3V supply when the relay is in energised state, whereas pin 2 is grounded. A resistor (R2) connected across pins 7 and 8 is used to fix the frequency of the inbuilt oscillator.

Circuit Diagram

Automatic Heat Detector Circuit Diagram

The output is available from pin 3. Two transistors BC147 (T3) and BEL187 (T4) are connected in Darlington configuration to amplify the sound from UM3561. Resistor R4 in series with a 3V zener is used to provide the 3V supply to UM3561 when the relay is in energised state. LED1, connected in series with 68-ohm resistor R1 across resistor R4, glows when the siren is on. To test the working of the circuit, bring a burning matchstick close to transistor T1 (BC109), which causes the resistance of its emitter-collector junction to go low due to a rise in temperature and it starts conducting. Simultaneously, transistor T2 also conducts because its base is connected to the collector of transistor T1. As a result, relay RL1 energizes and switches on the siren circuit to produce loud sound of a fire-brigade siren.

Note.

We have added a table to enable readers to obtain all possible sound effects by returning pins 1 and 2 as suggested in the table.

Author:Sukant Kumar Behara Copyright:Circuit Ideas

Wednesday, September 11, 2013

Build a Telephone Record Control Circuit Diagram

This simple Telephone Record Control Circuit Diagram will allow you to connect any tape recorder that has a mic and remote input to a phone line and automatically record both sides of a conversation when ever the phone is in use. You will need to take a couple of voltage readings before connecting the circuit. First determine the polarity of your phone line and connect it to the circuit as shown and then determine the polarity of the remote input and connect it to the circuit.

Circuit operation is as follows. When the phone is on hook the voltage across the phone line is about 48volts dc. When the phone is off hook the voltage will drop to below 10volts dc. When the line voltage is at 48volts the FET is off which causes Q2 and Q3 to be off. When the phone is picked up the FET turns on along with Q2 and Q3 which turns your recorder on. The tape recorder must be in the record mode at all times. As you can see the power source for the circuit is the phone line.

Telephone Record Control Circuit Diagram

Telephone Record Control Circuit Diagram

Thursday, September 5, 2013

LED 12 Volt Lead Acid Battery Meter Circuit

In the circuit below, a quad voltage comparator (LM339) is used as a simple bar graph meter to indicate the charge condition of a 12 volt, lead acid battery. A 5 volt reference voltage is connected to each of the (+) inputs of the four comparators and the (-) inputs are connected to successive points along a voltage divider. The LEDs will illuminate when the voltage at the negative (-) input exceeds the reference voltage. Calibration can be done by adjusting the 2K potentiometer so that all four LEDs illuminate when the battery voltage is 12.7 volts, indicating full charge with no load on the battery. At 11.7 volts, the LEDs should be off indicating a dead battery. Each LED represents an approximate 25% change in charge condition or 300 millivolts, so that 3 LEDs indicate 75%, 2 LEDs indicate 50%, etc. The actual voltages will depend on temperature conditions and battery type, wet cell, gel cell etc.

Circuit Diagram

Source http://www.bowdenshobbycircuits.info/

Monday, September 2, 2013

Simple AM Transmitter Circuit

Circuit Diagram:

Description

There are not many AM transmitters that are easier to build than this one because the inductor is not tapped and has a single winding. There is no need to wind the inductor as it is a readily available RF choke (eg, Jaycar Cat LF-1536). To make the circuit as small as possible, the conventional tuning capacitor has been dispensed with and fixed 220pF capacitors used instead. To tune it to a particular frequency, reduce one or both of the 220pF capacitors to raise the frequency or add capacitance in parallel to lower the frequency. Q1 is biased with a 1MO resistor to give a high input impedance and this allows the use of a crystal ear piece as a low cost microphone.

Author: Peter Goodwin
Source http://www.extremecircuits.net/2010/05/simple-am-transmitter.html

Friday, May 17, 2013

LM3900 Audio Mixer Circuit

LM3900 Audio Mixer Circuit

LM3900 Audio Mixer Circuit

Audio mixer circuit consists of 4 four-channel amplifier (LM3900) two microphone inputs and two audio inputs are available directly online at this circuit. By adding the parallel with this circuit, you can increase the number of entries according to applications. Each input is connected to the inverting terminal of the LM3900.

The amplifier built in each section amplifies each audio input separately and fed to the output terminals. The output terminal of each channel is connected to a single output line with a resistance no greater than 680 and produces a mixture of audio output with low noise. This audio mixer circuit does not use a low impedance input sources to the mix of ideals. Capacitors C1 to C4 are decoupling capacitors corresponding channels. C5 is the decoupling capacitor production.

Tuesday, May 14, 2013

Relay Delay circuit

This is a relay delay circuit.By using this circuit we can delay the function though circuit gave the signal.That means there is some time to operate the relay after the signal which gave form the circuit.here you can get 6 second delay.But if you want more you can do it changing the value of capacitor.If you use 470uf it will delay 20 seconds.

Monday, May 13, 2013

touch switch circuit

The modern mechanic switches are improved concerning of old technology. We need however many times to replacement some old switch or to check currents bigger than the durability of certain switches or simple we need something with modern appearance. For he and different reasons is essential the up circuit. It is simple in the manufacture and the materials that use they exist everywhere.

Parts:
R1 = 3.3M
R2 = 3.3M
R3 = 10K R4 = 1K
C1 = 10nF-63V
D1 = 1N4007
D2 = Red LED
Q1 = BC547
IC1 = NE555
RL1 = 12V Relay This circuit is based on the well known timer IC 555 (IC1),

which drives a relay of which the contacts play the role of switch. The metal surfaces can have what form we want, but it should they are clean and near in the circuit. In order to it changes situation it suffices touch soft somebody from the two plates. Plate MP1 in order to the contacts of RL1 close [ON], or plate MP2 in order to the contacts of RL1 open [OFF]. The current that RL1 will check depended from his contacts. The Led D2 turns on when the switch they are in place ON and the contacts of RL1 closed. Two small pieces of metal can be used instead of MP1 – MP2. Because MP = Metal Plate.

Sunday, May 5, 2013

Lights Control for Model Cars Circuit Diagram

The author gave his partner a radio controlled (RC) model car as a gif t. She found it a lot of fun, but thought that adding realistic lights would be a definite improvement. So the author went back to his shed, plugged in his soldering iron, and set to work equipping the car with realistic indicators, headlights, tail lights and brake lights.

Lights Control for Model Cars Circuit Diagram

The basic idea was to tap into the signal from the radio control receiver and, with a bit of help from a microcontroller, simulate indicators using flashing yellow LEDs and brake lights using red LEDs. Further red LEDs are used for the tail lights, and white LEDs for the headlights. Connectors JP4 and JP5 (channel 0) are wired in parallel, as are JP6 and JP7 (channel 1), allowing the circuit to be inserted into the servo control cables for the steering and drive motor respectively. The ATtiny45 micro-controller takes power from the radio receiver via diode D1. T1 and T2 buffer the servo signals to protect IC1’s inputs from damage.

IC1 analyses the PWM servo signals and gen-erates suitable outputs to switch the LEDs via the driver transistors. T3 drives the two left indicators (yellow), T4 the two right indica-tors, and T5 the brake LEDs (red). The red tail lights (JP2-8 and JP2-8) and the white head-lights (JP2-9 and JP2-10) are lit continuously. The brake lights are driven with a full 20 mA, so that they are noticeably brighter than the tail lights, which only receive 5 mA. If you wish to combine the functions of tail light and brake light, saving t wo red LEDs, sim-ply connect pin 10 of JP2 to pin 14 and pin 12 to pin 16. Then connect the two combined brake/tail LEDs either at JP2-5 and JP2-6 or at JP2-7 and JP2-8.

JP3 is provided to allow the use of a separate lighting supply. This can either be connected to an additional four-cell battery pack or to the main supply for the drive motor. The val-ues given for resistors R8 to R17 are suitable for use with a 4.8 V supply. JP2 can take the form of a 2x10 header.

As usual the sof t ware is available as a free download from the Elektor web pages accom-panying this article[1], and ready-programmed microcontrollers are also available. The microcontroller must be taught what servo signals correspond to left and right turns, and to full throttle and full braking. First connect the fin-ished circuit to the radio control electronics in the car, making sure everything is switched of f. Fit jumper JP1 to enable configuration mode, switch on the radio control transmit-ter, set all proportional controls to their cen-tre positions, and then switch on the receiver. The indicator LEDs should first flash on both sides. Then the car will indicate left for 3 s: during this time quickly turn the steering on the radio control transmitter fully to the left and the throt tle to full reverse (maximum braking).

Hold the controls in this position until the car starts to indicate right. Then set the controls to their opposite extremes and hold them there until both sides flash again. Now, if the car has an internal combustion engine (and so cannot go in reverse), keep the throttle control on full; if the car has an electric motor, set the throttle to full reverse. Hold this position while both sides are flashing. Configuration is now complete and JP1 can be removed. If you make a mistake during the configuration process, start again from the beginning.

Author: Manfred Stratmann - Copyright : Elektor

Saturday, April 13, 2013

Amplified Ear Circuit

Useful to pay attention in faint sounds, 1.5V Battery operation

This circuit, related to 32 Ohm impedance mini-earphones, can discover very faraway sounds. Useful for theatre, cinema and lecture goers: every phrase will most probably be clearly heard. You may additionally hearken to your television set at an awfully low quantity, fending off to hassle household and neighbors. Even when you've got a flawless hearing, you may just additionally discover sudden sounds the usage of this device: a remote chicken twittering will seem very close to you.

Circuit Diagram:

$\"Amplified_Ear$ Amplified Ear Circuit Diagram

Parts :

P1 = 22K
R1 = 10K
R2 = 1M
R3 = 4K7
R4 = 100K
R5 = 3K9
R6 = 1K5
R7 = 100K
R8 = 100R
R9 = 10K
C1 = 100nF 63V
C2 = 100nF 63V
C3 = 1µF 63V
C4 = 10µF 25V
C5 = 470µF 25V
C6 = 1µF 63V
D1 = 1N4148
Q1 = BC547
Q2 = BC547
Q3 = BC547
Q4 = BC337
J1 = Stereo 3mm. Jack socket
B1 = 1.5V Battery (AA or AAA cell etc.)
SW1 = SPST Switch (Ganged with P1)
MIC1 = Miniature electret microphone

Circuit Operation :

The heart of the circuit is a continuing-volume keep watch over amplifier. All the alerts picked-up by using the microphone are amplified at a constant degree of about 1 Volt height to peak. In this fashion very low amplitude audio alerts are highly amplified and excessive amplitude ones are limited. This operation is entire by Q3, modifying the bias of Q1 (hence its AC gain) by means of R2.
A be consciousworthy function of this circuit is 1.5V battery operation. Typical present drawing: 7.5mA.

Notes:

Due to the constant-volume control, some users may imagine P1 quantity regulate needless. In most instances it may just be neglected, connecting C6 to C3. In this case use a SPST slider or toggle swap as SW1.
Please word the stereo output Jack socket (J1) connections: most effective the 2 inside connections are used, leaving open the exterior one. In this method the 2 earpieces are wired in series, permitting mono operation and most effective load impedance to Q4 (64 Ohm).
Using suitable miniature components, this circuit can additionally be enclosed in an awfully small field, provided via a clip and hanged on ones garments or slipped into a pocket.
Gary Pechon from Canada suggested that the Amplified Ear is so sensitive that he can hear a whisper 7 meters throughout the room.
He hooked a small relay coil to the input and used to be ready to locate energy traces in hellos wall. He used to be also ready to hear the neighbors stereo perfectly: he may pick up the indicators despatched to the speaker voice coil thru a plaster wall.
Gary suggests that this circuit might make additionally a excellent electronic stethoscope.

http://www.ecircuitslab.com/2011/06/amplified-ear-circuit.html

Simple Mobile Phone Jammer Circuit Diagram

Description
Circuit displaying a cell phone jammer.Here i have used a fm transistor for making this circuit.Mobile cellphones are working in 450 MHz frequency .Here the transmitter generate virtually equal to 450 MHz frequency there for the mobile telephone does not determine the original signal however the sign range may be very week so this circuit working in most effective 100 m range .This circuit working in handiest 450 Mhz .Do now not supply extra than three V

Part List

Component No:	Value	Usage
R1	100R	Emitter loading
R2	39k	Base Biasing
C1	15 pf	Frequency Generating
C2	4.7pf	Feedback
C3	4.7pf	Feedback
C4	102pf	Noise Reduce
C5	1MF	Coupling
C6	2.2pf	Coupling
C7	103pf	Decoupling
Q1	BF 494	Amplification
L1	22nH	Frequency Generating

Applications

* FM Transmission

* TV Transmission

* Remote Controlled Toy

Friday, April 12, 2013

Simple AM Transmitter Circuit

AM
transmitter circuit that can transmit your audios to your backyard.This
circuit is designed with limited the power output to match the FCC
regulations and still produces enough amplitude modulation of voice in
the medium wave band to satisfy your personal needs. You will love
this.

The circuit has two parts , an audio amplifier and a radio frequency oscillator. The oscillator
is built around Q1 (BC109) and related components. The tank circuit
with inductance L1 and capacitance VC1 is tunable in the range of 500kHz
to 1600KHz.

These
components can be easily obtained from your old medium wave radio. Q1
is provided with regenerative feedback by connecting the base and
collector of Q1 to opposite ends of the tank circuit. C2 ,the 1nF capacitance
, couples signals from the base to the top of L1, and C4 the 100pF
capacitance ensures that the oscillation is transfered from collector,
to the emitter, and through the internal base emitter resistance of the
transistor Q2 (BC 109) , back to the base again.

The
resistor R7 has a vital part in this circuit. It ensures that the
oscillation will not be shunted to ground trough the very low value
internal emitter resistance, re of Q1(BC 109), and also increases the
input impedance such that the modulation signal will not be shunted to
ground.

Q2
is wired as a common emitter RF amplifier, C5 decouples the emitter
resistance and unleashes full gain of this stage. The microphone can be
electret condenser microphone and the amount of AM modulation can be
adjusted by the 4.7 K variable resistanceR5.

Wednesday, April 10, 2013

230Vac Lamp Toggle Switch Circuit

Compact, transformerless circuitry No relays employed

Due to the low current drawing, the circuit can be supplied from 230Vac mains without a transformer. Supply voltage is reduced to 12Vdc by means of C1 reactance, a two diode rectifier cell D1 & D2 and Zener diode D3. IC1A, IC1B, R2, R3 and C3 form a reliable bounce-free toggle switch operated by P1. R4 and C4, wired to pin #6 of IC1B reset the circuit (lamp off) when power supply is applied. IC1C and IC1D wired in parallel act as a buffer, driving the Gate of the Triac through R5.

Circuit Diagram :

230Vac Lamp Toggle Switch Circuit diagram

Parts:

R1____________470R   1/2W Resistor
R2_____________10K   1/4W Resistor
R3,R4_________100K   1/4W Resistors
R5______________1K   1/4W Resistor

C1____________330nF 400V Polyester Capacitor
C2____________100µF   25V Electrolytic Capacitor
C3____________100nF   63V Polyester or Ceramic Capacitor
C4_____________10µF   25V Electrolytic Capacitor

D1,D2________1N4007 1000V 1A Diodes
D3_________BZX79C12   12V 500mW Zener Diode
D4__________TIC206M 600V 4A TRIAC

IC1____________4011 Quad 2 Input NAND Gate CMos IC

P1_____________SPST Pushbutton

Note:

he circuit can be wired permanently to the mains supply as current drain is negligible.

Due to transformerless design there is no heat generation.

Low Gate-current Triacs are recommended.

Obviously, other appliances can be powered in place of a lamp, provided their power dissipation does not exceed about 400W @ 230V

110-120Vac operation is easily obtained by simply changing C1 value to 680nF 250V. No further changes are necessary.

In some cases, e.g. when the controlled device is far from the toggle switch, a pilot LED could be necessary for monitoring purposes. If so, disconnect pin #10 of IC1C from pin #11 of IC1D and wire a LED and its 1K series current limiting resistor across pin #10 of IC1C and negative supply.

Warning! The circuit is connected to 230Vac mains, so some parts in the circuit board are subjected to lethal potential! Avoid touching the circuit when plugged in and enclose it in a plastic box.

Source: www.redcircuits.com

Tuesday, April 9, 2013

Audio Peak Indicator Circuit

The existence of the peak indicator "Audio Peak Indicator" in an audio device is needed. Audio Peak indicator is a simple circuit to detect the peak level of audio signal. Audio Peak indicator circuit is built with duabuah transistor and LED indicator as peak level detection of audio signals.

The main function of a series of Audio Peak indicator is to determine the occurrence of the peak level of audio signal that is more than +4 dB, equivalent to 1.25 V rms. If the received audio signal Audio Peak Indicator more than +4 dB was the LEDs in series Peak Audio This indicator will light. Audio Peak indicator circuit is mounted on the output audio system.

Audio Peak Indicator Component List:
R1 = 10Kohm
R2 = 1.2Kohm
R3 = 220Kohm
R4-5 = 4.7Kohm
C1 = 47uF 25V
C2 = 2.2uF 25V
Q1-2 = BC550C
D1 = LED RED

We hope to form the reference materials in the manufacture of circuit pernagkat Audio Peak Indicators in the audio readers.

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