Electronic Schematic Diagram

Gold Detector Schematic

2012-04-20T20:30:00.003-07:00

Here the very simple and easy build gold detector circuit. The circuit capable to sense gold or metal or coins from a distance of about 20cm, depending on the size of the object to detect.

The circuit oscillates at about 140kHz and a harmonic of this frequency is detected by an AM radio. You can simply tune the radio receiver until a squeal is detected.

When the search coil is placed near a metal object, the frequency of the circuit will change and this will be heard from the speaker of AM radio.

Below image is the construction of the circuit, you will see that the radio is placed on the hand stick of the complete detector.

Simple Intercom Circuit with Transistors

2012-04-01T18:41:00.000-07:00

This is a 2-station simple intercom circuit build based on transistors part and using common 8R mini speakers. The speaker works as microphone and generate sound, so there is no need microphone for this intercom. The "press-to-talk" switches should have a spring-return so the intercom can never be left ON, push on switch can be used for this kind of task.

The secret to preventing instability (motor-boating) with a high gain circuit like this is to power the speaker from a separate power supply! You can connect an extra station (or two extra stations) to this circuit design.

Build the circuit into two separated boxes (for 2 stations). On each box should be use 2 ports for external power supply port (if you use external power supply, not battery) and connection port to other stations. Create some holes for speaker push on switch.

Interior Light Fader for Automobile

2012-03-11T21:34:00.000-07:00

Here the circuit diagram of Interior Light Fader for Automobile. The circuit is build using low power operational amplifier LM324 which only need around 3mA of current, so it won't bother the battery supply if left connected for extended periods. This circuit is similar to the fading eyes circuit above and is used to slowly brighten and fade interior lights of older cars.

The top two op-amps circuit module (pins 1,2,3 and 5,6,7) form a triangle wave oscillator running at about 700Hz while the lower op-amp (pins 8,9,10) produces a linear, 5 second ramp, that moves up or down depending on the position of the door switch. The two transistors and associated resistors serve to limit the ramp voltage to slightly more and less than the upper and lower limits of the triangle waveform. These two signals (700 hZ. triangle wave and 5 second ramp) are applied to the inputs of the 4th op-amp (pins 12,13,14) that serves as a voltage comparator and produce a varying duty cycle square wave that controls the IRFZ44 MOSFET and lamp brightness. The 5 second fade time can be adjusted with the 75K resistor connected to the door switch. A larger value will increase the time and a smaller value will speed it up.

When the door switch is closed (car door open) the voltage on pin 8 slowly increase above the negative peaks of the triangle wave producing a short duty cycle output and a dim light. As the ramp moves farther positive, a greater percentage of the triangle wave will be lower than the ramp voltage producing a wider pulse and brighter light. This process continues until the ramp is 100% above the positive peaks of the triangle wave and the output is maximum. When the door switch is open, the reverse action takes place and the lamps slowly fade out.

The MOSFET IRFZ44 shouldn't need a heatsink if the total load is 50 watts or less but the temperature of the MOSFET should be monitored to make sure it doesn't overheat. The on-state resistance is only 0.028 ohms so that 4A of current (48 watts) is only around 100mW. For larger loads, a compact heatsink can be added to keep the MOSFET cool. - Interior Light Fader for Automobile circuit diagram

Dynamic Mic Amplifier (To Use Speaker as Microphone)

2012-02-27T02:50:00.000-08:00

This is the circuit diagram of dynamic mic amplifier. This simple and easy built circuit can be used as a subtitute of an electret microphone. It will turn an ordinary mini speaker to become a pretty sensitive microphone.

Any NPN transistors can be applied for this circuit, for example: BC547. The circuit will operated from 3v to 9v DC supply. The amplifier configuration used in this dynamic mic amplifier is a common-base amplifier, it accepts the low impedance of the speaker to deliver a gain of more than 100 times.

Basic Oscillator Circuit using Two Transistors

2012-02-20T00:51:00.000-08:00

This is the schematic diagram of basic oscillator circuit which using two transistors. When two transistors and a couple of passive components are connected as shown in the figure, the circuit starts to oscillate. The frequency of oscillation can be adjusted by changing the values of either the resistor or the capacitor.

For easier experiment, you may replace the resistor with 10K potensiometer. By increasing its frequency to a suitably high level, it can be used to drive a speaker or a buzzer to produce an audio alarm note. By sufficiently reducing its frequency, the circuit may be used to flash a LED as a warning indicator.

The another circuit of two transistors oscillator described in the following video:

One Transistor LED Flasher Circuit

2012-02-14T19:46:00.000-08:00

Here the schematic diagram of one transistor LED flasher. This circuit can be the simplest circuit led flasher over the world.... :D

This is a novel flasher circuit working with a single driver transistor that will take its flash-rate from a flashing LED. The flasher in the photo is 3mm. An ordinary LED is not going to work. The flash rate are not able to be altered by the brightness of the high-bright white LED can be adjusted by replacing the 1k resistor across the 100uF electrolytic to 4k7 or 10k.

The 1k resistor discharges the 100uF so that when the transistor turns on, the charging current into the 100uF illuminates the white LED. If a 10k discharge resistor is applied, the 100uF will not be completely discharged and also the LED isn't going to flash as bright.

All of the components within the photo are in the identical places as in the circuit diagram in making it easy to learn how the components are joined.

Magic Lights Circuit using Bi-Colour LED

2012-02-05T20:03:00.000-08:00

This is the magic lights circuit which use bi-colour LED as the output to provide the light. The circuit uses 14 bi-colour (red and green) LEDs having 3 terminals each. Various dancing colour patterns are generated utilizing this circuit considering that each LED can create three various colours. The middle terminal (pin 2) of the LEDs will be the common cathode pin that is grounded. When a positive voltage is applied to pin one, it emits red light. Similarly, when positive voltage is applied to pin 3. it emits green light. And when positive voltage is simultaneously applied to its pins 1 and 3, it emits amber light.

The circuit could be implemented for decorative lights. The IC1 (timer IC 555) is applied in astable mode of multivibrator to produce clock signal for IC2 and IC3 (CD4518) that are dual BCD counters.

The two counters of each one of these ICs have already been cascaded to acquire 8 outputs from each. The outputs from IC2 and IC3 are connected to IC4 through IC7 that are BCD to 7-segment latch/decoder/driver ICs. Therefore we acquire a complete of 14 segment outputs from each of the IC pairs composed of IC4 plus IC5 and IC6 plus IC7. While outputs from former pair are connected to pin No. 1 of all the 14 bi-colour LEDs through current limiting resistors, the ouputs of the latter pair are similarly connected to pin No.3 of all the bi-colour LEDs to acquire a magical dancing lights effect.

Simple Audio Booster

2012-01-29T19:17:00.000-08:00

This is a simple and low-cost audio booster circuit design. The circuit is based on general purpose amplifier and switches, 2N3392 transistor packed in TO-92. This circuit should be installed before power amplifier module.

To get the maximum audio performance, use metalfilm resistors, MKM and tantalum capacitors which have small tolerance of its value. Also, use stabilized and regulated 9V power supply for better result. You can simply use LM7809 IC regulator on 12V power supply to get stabilized 9V output. The 100K variable resistor is used to adjust the volume, you may remove this component and use main volume in your audio system.

Cricket Chirping Sound Generator

2012-01-24T23:00:00.000-08:00

This is the circuit diagram of cricket chirping sound generator based on IC 4060, a 14 stage ripple counter and oscillator IC. A suitable audio wave form is produced by IC2 and related electronic components, driving the mini speaker through Q1. To allow a more real-life behavior, the chirp is interrupted in a pseudo-casual way by two timers built around IC1C and IC1D, whose outputs are mixed into IC1B and further time-delayed by IC1A, driving the reset pin of IC2.

An optional Photoresistor can be wired across this pin and positive supply, it is to make the circuit operates in the dark and stops when light is coming, thus imitating the cricket's behavior even more closely. R9 acts as volume control and can be a preset trimmer or a small potentiometer.

Components List:

R1 = 330K 1/4W
R2 = 220K 1/4W
R3,R6 = 100K 1/4W
R4 = Photo resistor (Optional, see text)
R5,R7 = 22K 1/4W
R8 = 10K 1/4W
R9 = 470R 1/2W Trimmer Cermet or Carbon
R10 = 22R 1/4W
C1,C2,C3 = 47µF/25V
C4 = 10µF/25V
C5 = 1µF/50V
C6 = 10nF/63V
D1,D2,D3,D4 = 1N4148
Q1 = BC547
IC1 = 4093
IC2 = 4060
SPKR = 8 Ohm
SW1 = SPST Toggle or Slide Switch
B1 = 9V PP3 Battery (See Notes)

Circuit Notes:

The circuit can be powered by any battery or power supply adapter with 5 - 12V range.
For maximum performance results please use a loudspeaker as small as possible.
In some cases, the chirp can be improved further on by pressing the loudspeaker against a flat surface, for example. a wooden table.

Cricket chirping sound generator circuit project, page source: extremecircuits.net

19W Power Amplifier based LA4440

2012-01-21T03:47:00.000-08:00

This is the 19W power amplifier circuit built based power IC LA4440. The LA4440 output configured in bridge connection. The LA4440 can be used for stereo amplifier and it will give power output of 6W on each channel. But if you use this power IC in bridge mode, the it will deliver power audio output up to 19W. Recommended supply voltage is 13.2V, 2A and heatsink should be mounted on the power IC.

Power IC LA4440 Features:

Built-in 2 channels (dual) enabling use in stereo and bridge amplifier applications.

Dual : 6W´2 (typ.)
Bridge : 19W (typ.)

Small pop noise at the time of power supply ON/OFF and good starting balance.
Minimum number of external parts required.
Good ripple rejection : 46dB (typ.)
Easy to design radiator fin.
Low distortion over a wide range from low frequencies to high frequencies.
Small residual noise (Rg=0).
Good channel separation.
Built-in protectors.
Built-in audio muting function.

Overvoltage, surge voltage protector
Thermal protector
Pin-to-pin short protector

Download the database of LA4440

15W Audio Amplifier with STK055

2012-01-13T15:41:00.000-08:00

Here the schematic diagram of 15W audio amplifier, built based on single power chip STK055 from Sanyo.The STK055 is old power amplifier chip which still available on the market because of the ease of its usage and the performance is good. This chip requires heatsink to be mounted on its body.

Technical details:

Maximum power supply: ± 28V
Recommended supply voltage: ± 20V
Power output: 15W
RL: 8 Ohm
TDH: 0.3%
Rin: 52K
Gain: 26.4 dB
Noise: 0.3mV

Mice Repellent Circuit

2012-01-08T05:01:00.000-08:00

This is the circuit diagram of mice repellent. Mice are animals that are very annoying, because sometimes he is damaging the object stored in the form of archives that are still valuable.

To drive out the mice, you can create an electronic circuit of mice repellent as shown above. With 50KHz frequency generated by the timer IC 555. The mice would run because his ears will feel sore due to the signal frequency.

The work of this circuit is very simple. The timer IC act as the frequency generator, while the frequency value is decided by C1 and C3. The output of 555 will be amplified by the SC1162 transistor and then fed to the speaker so the audio signal can be heard by the mice.

Parts List:

R1 = 1K8
R2 = 1K
R3 = 5K6
R4 = 480R
C1 = 2,2nF
C2 = 0,022uF/6V
IC = 555
Q = SC1162
SP = Speaker 4 ohm

Surround Sound Processor Circuit

2012-01-02T14:55:00.000-08:00

This is the easy build surround sound processor circuit using the digital delay process method. This audio processor isn't applying any unique function ICs that tough to obtain parsonaly, and designed in only common purpose ICs.

The kind of this Surround Processor is producing the surround impact with processing two channels of stereo supply. The majority of those are generates the surround impact with separates reverberations from supply signal and applies any processes, after which mix it to front channels or output as rear channel.

The circuit works and contains three modules:

Separating the Reverberatins

The distinction in between each channels is separated with distinction amplifier from the op-amp. And greater frequencies inside the distinction signal are cut using the LPF.

A-D and D-A conversion

These are composed with common purpose ICs. The A-D converter is basically delta modurator that making use of a comparator plus a D type flip-flop. And it converts analog signal into digital data of one bit, 2 Msa/sec. Following passed digital delay, the bit stream is directly conversion into analog signal using the integrater.

It isn't beneficial that signal to noise ratio and distortion as this A-D, D-A converter.

Digital Delay

For the digital delay method, a DRAM chip is utilised as a FIFO memory. This circuit design demands a 64K bit DRAM, but I utilized a 256K bit DRAM discovered within the junk box. Shift register generates Read-Modify-Write cycle, read out old data and save new data in a single cycle.

And lower byte in the address counter is assined as row address with the DRAM to increment row address every single cycle, to ensure that refresh cycle is often omitted. The FIFO length is 65536 bits and 2 Msa/sec makes 33 msec of delay time.

Surround sound processor circuit source page: http://elm-chan.org/works/srp/report_e.html

Mic Preamplifier Circuit based TLC251

2011-12-25T16:13:00.000-08:00

Here the schematic diagram of mic preamplifier which build based on operational amplifier TC251. The TLC251 is operating in low bias. The circuit works with only 1.5 V supply draws electric current of only 10 mA, so the battery operation will be prefered. Circuit frequency response is 3dB, 27 Hz to 4.8 kHz.

Frequency Response:

The TLC251 are low-cost, low-power programmable operational amplifiers designed to operate with single or dual power supplies. Because the input common-mode range extends to the negative rail and the power consumption is very low, this chip is ideally suited for battery-powered or energy-conserving applications. A bias-select pin can be used to program one of three ac performance and power-dissipation levels to suit the application. The series features operation down to a 1.4V supply and is stable at unity gain.

Download the TLC251 datasheet document from the following link:
» Download link

Stereo Tube Power Amplifier Schematic

2011-12-18T21:23:00.000-08:00

This is the circuit diagram of stereo tube power amplifier. It applies 3 types of tube that are 2 6SF5 GT high-mu triodes, 1 5Y3 GT vacuum rectifier, and 2 6K6 power beam amplifiers. The Audio input can be from any two-channel line level device such as a television, CD player, or VCR. It is of the tube type, using only 5 tubes total with no more than about 45 Watts power consumption from the outlet.

Components List:
R1,R10,R13 = 2.2M Ohm Potensiometer
R2 = 470K Ohm
R3 = 1M Ohm
R4 = 220K Ohm
R5 = 330 Ohm 2W Resistor
R6 = 220K Ohm
R7 = 2.2M Ohm
R8 = 1M Ohm
R9 = 720 Ohm 20W Resistor
R11 = 33K Ohm
R12 = 22K Ohm
C1,C9 = 4nF 400V Capacitor
C2 = 50nF 600V Capacitor
C3 = 20uF/25V
C4 = 10nF 400V Capacitor
C5 = 200pF 400V Ceramic Disc Capacitor
C6,C7 = 15uF 450V Capacitor
C8 = 15uF 400V Capacitor
T1 = 117V Primary, 350VCT Secondary, 6.3V Secondary, 6.3V Secondary
T2 = 7600 Ohm Primary, 4 or 8 Ohm Secondary
SW1 = SPST Switch
SP1,SP2 = 12" or smaller, 4 or 8 ohm speakers
MISC = 5 tube sockets, 2 RCA jacks, PC board or chassis, wire, knobs, etc.

Stereo Tube Power Amplifier Circuit Notes:

C8 is for radio interference suppression and may be omitted.
The 6V6 GT tube may be substituted for the 6K6 to lower power requirements.
The 5Y3 GT tube should be mounted in a vertical position and be well ventilated. The 6K6 and 6SF5 tubes can be mounted in any position.
The power supply portion of this unit may be used for anything requiring 290-320v DC up to about 3 amperes.
Controls should have an audio taper.

Circuit Source: http://english.cxem.net/amplifier/amplifier13.php

12 LED VU Meter Circuit

2011-11-22T23:30:00.001-08:00

Here the 12 LED VU meter circuit. This is a simple visual indication of the audio level signals, adaptive to various user needs. Can be adapted to different input levels, adjustable by trimmer TR1 (state) - TR2 (Gain), then rectified by diodes D1-D2 (standard negative mark-recovery periods) and driven in the main circuit indication, consisting of the diodes D3 up to D13, transistors Q2-Q13 and materials that exist around them.

The visual indicator is taken from the series of diodes LED LD1-13. Each Led illuminates when the level changed during about 0,65 V. The power requirements are 100 ma full term. We can add as many steps we want LED, always assuming the power where you need the new LED.

Components List

R1 = 47Kohm
R2,3 = 1Mohm
R4,R7 = 1Kohm
R5 = 100ohm
R6 = 18Kohm
R9,11,13,15,17 = 560ohm
R19,21,23,25,27 = 560ohm
R29,31 = 560ohm
R8,10,12,14 = 4.7Kohm
R16,18,20,22 = 4.7Kohm
R24,26,28,30 = 4.7Kohm
C1 = 10uF/25V
C2 = 100nF/100V MKT
C3 = 4.7uF/25V

C4 = 4.7uF/25V
C5 = 10uF/25V
C6 = 47uF/25V
C7-8 = 100nF/100V
TR1 = 100Kohm Trimmer
TR2 = 4.7Kohm Trimmer
LD1 until LD7 = LED Green
LD8,LD9,LD10 = LED Yellow
LD11,LD12,LD13 = LED Red
D1 until D13 = 1N4148
Q1 until Q13 = BC550C - BC549B
IC1 = TL071
IC2 = 7812 [With Heatsink]
All Resistors is 1/4W 1 -5%

12 LED VU Meter Circuit source page: users.otenet.gr

2-Way Active Crossover Circuit

2011-11-12T02:44:00.001-08:00

This is the schematic diagram of 2-way active crossover circuit. The "active" word means that the circuit use active component and need power supply to work. Take a note that the input of this circuit is not connected to the output of power amplifier. This crossover circuit module must be placed before the amplifier circuit. The "Low Out" output connected to a power amplifier and the low speaker [Woofer], while the "High Out" output is drive the power amplifier of high speaker [Tweeter].

Parts List

R1 = 100Kohms
R2,3,4,5,6 = 37.5ohms [33K+4.7K]
R7 = 75Kohms[150K//150K
R8 = N.C
R9,10,11,12,13,14,15,16 = 10Kohms
R17,18 = 47Kohms
R19,20 = 47ohms
C1 = 4.7uF/100V MKT
C2,3,4,5,6,7,12,13 = 1nF 100V MKT
C8,9,10,11,14,15 = 100nF 100V MKT
C16 = 2.2uF/100V MKT
C17 = 470nF 100V MKT
C18,19 = 47uF/25V
J1,2,3 = 2pin conn. 2.54mm pin step
J4 = 3pin conn. 2.54mm pin step
IC1,2,3 = NE5532 , TL072
TR1 = 100Kohms trim. or pot.
TR2,3 = 47Kohms trim. or pot.
All the Resistors is 1,2% 1/4W metal film

Circuit Source: 2-Way Active Crossover Circuit with Linear Phase Response

Home Telephone FM Transmitter Circuit

2011-11-01T03:04:00.000-07:00

Here the schematic diagram of home telephone FM transmitter. This circuit connects in series with your home phone line and delivers the phone conversation through the FM band any time you pick up the telephone handset. Transmitted signal could be tuned by any FM receiver. The circuit features an "On Air" LED indicator and also gives you a switch that can be utilized to turn off the transmitter. A special characteristic of the circuit is the fact that no battery is required to operate the circuit because electrical power is taken from your phone line.

The transmitter circuit works by using only a short piece of wire aerial about 4" / 10 cm long to transmit the signal and a portion of the RF signal can also be radiated via the phone line itself. The circuit may possibly be implemented to share or record conversations, but will not be meant for illegal use.

Source: Home Telephone FM Transmitter Circuit

Stereo PLL FM Transmitter based BH1417

2011-10-26T04:39:00.000-07:00

Here the circuit diagram of stereo PLL FM transmitter based BH1417 chip. This is certainly the most recent BH1417 FM Transmitter design diagram from RHOM that consists of lots of capabilities in a single tiny package. It includes pre-emphasis, limiter to ensure that the music can be transmitted at the same audio level, stereo encoder for stereo transmission, low pass filter that blocks any audio signals above 15KHz to avoid any RF interference, PLL circuit that delivers rock solid frequency transmission (no extra frequency drift), FM oscillator and RF output buffer.

There is certainly 14 possible transmission frequencies with 200KHz increments that you can select using a 4-DIP switch. Lower band frequencies begin from 88.7 up to 89.9 MHz, and upper band frequencies begin from 107.7 up to 108.9 MHz.

BH1417 could be supplied with 4 - 6 voltage and needs only about 30mA, giving 20mW output RF power. BH1417 delivers 40dB channel separation that is fairly good, although older BA1404 FM Transmitter chip delivers slightly better 45dB channel separation.

BH1417 is only offered in SOP22 IC case so this may possibly be an inconvenience for some people. On the other hand, since the chip is smaller than common DIP-based ICs it's possible to fit the whole transmitter on a compact PCB.

BH1417 chip may possibly also be applied a stand alone stereo encoder. The benefit of that's that you have full freedom of working with a transmitter and amplifier of your choice. You will still have a pre-emphasis, limiter, stereo encoder and low pass filter in a single tiny package since very few external components are required for these blocks. PIN 5 is MPX output that could be directly connected to an external FM transmitter through a 10uF capacitor.

Detailed information about this circuit, visit: http://electronics-diy.com/BH1417_PLL_Stereo_FM_Transmitter.php . The kit of stereo PLL FM transmitter based BH1417 also available there.

FM Transmitter Circuit with MAX2606

2011-10-21T19:04:00.000-07:00

FM transmitter circuit which is build using single chip of MAX2606. A very simple FM transmitter connects your home-entertainment system to a portable radio that will be carried surrounding the house and into the back yard. As an example, it is possible to play music on the CD player in your private room, and listen to it on a portable radio by the back-yard barbeque.

IC1 is a voltage-controlled oscillator with integrated varactor. Its nominal frequency of oscillation is set by inductor L1, and a 390nH value places that frequency at 100MHz. Potentiometer R1 then allows you to choose a channel by tuning above the FM band of 88MHz to 108MHz. Output power is about -21dBm into 50 (most nations accept emissions below 10dBm in the FM band).

The home system's left and right audio signals are summed by R3 and R4, and attenuated by the (optional) potentiometer R2. R2's wiper signal serves as a volume adjustment by modulating the RF frequency. Signals above 60mV introduce distortion, so the pot attenuates down from that level.

In the absence of a common FM radio antenna, 75cm (30 inches) of wire will suffice as a transmitting antenna. For most effective reception, it need to be mounted parallel with the receiving antenna. The IC operates on a single power supply voltage inside the range 3V to 5V, but it is best to regulate the applied voltage to reduce frequency drift and noise.

80W Power Amplifier Circuit

2011-09-24T19:44:00.000-07:00

80W power amplifier circuit diagram based MJL4281A / MJL4302A and MJE15034 / MJE15035 power transistor. Actually the output power range is about 60W to 80W. This is an incredibly excellent amplifier. It's easy to construct, applies generally offered parts and is stable and well-performing. The diagram featured is really a full update on the original project, and even though it has a lot of similarities, is definitely a different design.

This amplifier circuit, even though extremely simple, is capable of great performance. This is not an amp to be under estimated, as the sonics are pretty good indeed, and this really is due (in part, at least) to the inherent simplicity of the diagram design. The amplifier is exceptionally quiet, and is reasonably tolerant of hard loads. It's an perfect amplifier for biamped systems, and may possibly be operated in bridge mode (BTL) in case you apply the suggested output transistors (which have the required power ratings).

Go to this 60-80W power amplifier page to get the detailed information about the circuit.

CMoy Headphone Amplifier Circuit

2011-09-15T04:21:00.000-07:00

The following diagram is the circuit of CMoy headphone amplifier. Chu Moy designed a very popular headphone amplifier that’s easy to build, and it can be built small enough to fit in a pocket, power supply and all. It’s powerful enough to drive very inefficient headphones to thunderous volumes from even weak sources

CMoy headphone amplifier circuit diagram:

The op-amp used for this circuit is OPA2132PA, you may use OPA2132P or OPA2134PA as the alternative op-amp chip.

Power supply circuit for CMoy headphone amplifier:

Go to this page for the complete tutorial of CMoy headphone amplifier circuit.

Multi-color LED Driver Schematic

2011-09-05T15:05:00.000-07:00

Have you ever wondered how many various colours can illuminate a LED? One, two or possibly three? Making this simple circuit, you will discover it a lot more. The important component in this design is a dual LED. One such accessory includes two inside the 'slices' of different diode LED, that each and every of them produces a different color (commonly green and red). For the drive needs three pins, a common cathode and two separate roots. In this way every single of the two integrated diodes can light up as independent of one another. You'll find only two colors that may create this dual LED.

Setting appropriate percentage of the currents flowing via two separate channels of the POY is, we have other from pure green and red, orange (IR = 21G) and yellow (IG = 2IR). In this circuit, the anodes of the double LED driven by the outputs a six-point buffer tri-state technology CMOS. As opposed to most integrated family of CMOS 4000, the 4503 applied here, can supply many different loads on high currents of the order of 10 mA. The stream that goes towards the two diodes is limited by the resistors R1 to R6 whose specific values are those that attain the distinct colors and changing brightness them. The circuit was originally created to display three various situations, each expressed their the presence of logical '1 'in one of the inputs a, b, c. The entries are able to activate only one of every single time, and if none of them had been excited, a NAND gate (IC1c) ensured that the LED 'to create fourth color. In the improved version we present these days, the circuit has added another level oscillator (IC 1 a and IC1b), which produces about two pulses per second. The pulses are introduced in the entrance activation OA (pin 1) of 4503, resulting in colorful flashes. The oscillator is controlled by the of logical statements applied to the inputs 'd' and 'e'. If both are simultaneously logical '1 ', then each the oscillator and also the buffers of 4503 stay inoperative. If e = 1 and d = 1, then all buffers are driven in a state of high resistance plus the circuit absorbs the least feasible electric current (standby). The power supply circuit was initially set at 12 Volt, but all of the components that are able to work equally properly with any voltage in between 5 Volt and 16 Volt.

6V Gel Cell Charger Circuit

2011-08-25T06:31:00.000-07:00

This is the diagram of 6V Gel Cell charger. The circuit is using NE555 timer as oscillator and TPI31T switching transistor. The schematic diagram designed by Tony Van Roon.

Parts List:

R1 = 22 ohm, 1W
R2 = 270 ohm
R3 = 220 ohm
*R4 = 715 ohm, 1%
*R5 = 3.57K, 1%
*R6 = 1.40K, 1%
*R7 = 1.47K, 1%

C1 = 100nF
C2 = 100nF
D1 = 1N4001
T1 = TIP31A, B, C (or equivalent)
U1 = Timer IC NE555V (or equivalent)
S1 = Toggle switch, ON-OFF

* Resistors type are carbon, 1/4 watt, 5% tolerance, unless otherwise indicated.

6V Gel Cell Charger circuit source page

6-8A / 0-28V Variable Power Supply Circuit

2011-08-18T02:33:00.000-07:00

This is the schematic diagram of variable power supply. The output voltage of this power supply circuit can be adjust from 0V to 28V DC, while the current output is static the rang is about 6A up to 8A.

Parts List:

R1 = 2K2 Ohm 2,5 Watt
R2 = 240 Ohm
R3,R4 = 0.1 Ohm 10 Watt
R7 = 6K8 Ohm
R8 = 10K Ohm
R9 = 47 Ohm 0.5 Watt
R10 = 8K2 Ohm
C1, C7, C9 = 47nF
C2 = 4700uF/50v – 6800uF/50v
C3, C5 = 10uF/50v
C4, C6 = 100nF
C8 = 330uF/50v
C10 = 1uF/16v
C11 = 22nF

D1…D4 = four MR750 diodes (MR750 = 6 Ampere diode) or 2 x 4 1N5401 diodes.
D5 = 1N4148, 1N4448, 1N4151
D6 = 1N4001
D10 = 1N5401
D11 = LED
D7, D8, D9 = 1N4001
TR = 2 x 15 volt (30volt total) 6+- Ampere
IC1 = LM317
T1, T2 = 2N3055
P1 = 5k
P2 = 47 Ohm or 220 Ohm 1 Watt
P3 = 10k trimmer pot
F1 = 1 Amp
F2 = 10 amp

Source: circuitdiagram.net