Electronic Schematic Diagram

Running LED

2009-06-28T00:19:00.000-07:00

This is the running LED circuit diagram. The LED will "running" (on) one by one. You can use this circuit for many purpose like motorcycle lamp, running character and much more.

Here the schematic diagram with IC timer 555:

And use this circuit use NAND logic:

Zone Alarm System

2009-06-18T16:43:00.000-07:00

This is the circuit of alarm system with 5 independent zones. Suitable for a small office or home environment. It uses just 3 CMOS IC's and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a "system armed" indicator.

Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 - 5 are immediate zones, which will trigger the alarm with no delay. Some RF immunity is provided for long wiring runs by the input capacitors, C1-C5. C7 and R14 also form a transient suppresser. The key switch acts as the Set/Unset and Reset switch. For good security this should be the metal type with a key.

Circuit works:
At switch on, C6 will charge via R11, this acts as the exit delay and is set to around 30 seconds. This can be altered by varying either C6 or R11. Once the timing period has elapsed, LED6 will light, meaning the system is armed. LED6 may be mounted externally (at the bell box for example) and provides visual indication that the system has set. Once set any contact that opens will trigger the alarm, including Zone 1. To prevent triggering the alarm on entry to the building, the concealed re-entry switch must be operated. This will discharge C6 and start the entry timer. The re-entry switch could be a concealed reed switch, located anywhere in a door frame, but invisible to the eye. The panic switch, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.

Simple Electronic Buzzer

2009-06-14T17:45:00.000-07:00

This is a simple electronic buzzer circuit diagram. Cheap and easy to build.
The 555 is used as astable multivibrator operating at about 1kHz and produces a shrill noise when switched on. The frequency can be adjusted by varying the 10K resistor. You may change the 10K resistor with variable resistor.

Variable Power Supply with L200

2009-06-06T17:13:00.000-07:00

This is adjustable power supply schematic diagram with IC L200 for its power regulation.

Voltage output is controlled by 10K variable resistor. Output voltage range value will be about 3 to 15 volts, and current range is about 10mA minimum and 2 amp maximum. Reaching the current limit will reduce the output voltage to zero.

Power Audio Amplifier based on STK400xx

2009-06-01T21:18:00.000-07:00

This is Power Audio Amplifier circuit based on STK400xx series. It's will give you very good quality of sound this circuit is unexpensive too since STK40xx series have low price. It is easy we make a power amplifier using only few external components. The STKxxxx amplifiers, for them we will find in enough eponymous stereo amplifiers , but also in enough activety loudspeakers. They do not need a lot of special knowledge of manufacture, only that attention in pins, in order to they do not break, and one good power supply.

Schematic Diagram:

Component Part list

R1-4 =1Kohm
R2= 33Kohm
R3-8=100ohm
R5= 0.22ohm 5W
R6=10ohm 2W
R7= 6,8ohm 2W
R9=12Kohm
R10=10Kohm
R11= 680ohm
C1=560 pF 100V ceramic or mylar
C2-7 =1 uF 63V MKT

C3-12 =220 uF 63V
C4-5-10 =100 pF
C6-9 =47uF 63V
C8 =100 nF 100V MKT
C11 =1 nF 100V MKT
C13 =100 uF 25V
C14=10pF 100V ceramic or mylar
L1 =3μH [15 turns of 1mm around R6]
100V ceramic or mylar
F1-2 =2A Fuse fast
IC1=STK4036......STK4044

STK40xx Series:

STK 4036 > Supply: ±35V - ±53,5V; Power (8R load): 50W
STK 4038 > Supply: ±40V - ±58V; Power (8R load): 60W
STK 4040 > Supply: ±43V - ±63V; Power (8R load): 70W
STK 4042 > Supply: ±46V - ±67V; Power (8R load): 80W
STK 4044 > Supply: ±51V - ±74V ; Power (8R load): 100V

High-End Audio Modular Preamplifier

2009-05-27T18:18:00.000-07:00

This circuit isn't easy to built but you will get a great audio quality from this circuit. This circuit will give u a high quality preamplifier, capable to drive high quality power amplifiers with good sound.

See the explanation here.

Digital Clock

2009-05-21T07:04:00.000-07:00

This is digital clock schematic diagram. You can find the complete explanatio include the component part list on the original page.

Small Surround Sound Decoder

2009-05-21T05:30:00.000-07:00

This is surround sound decoder. With this circuit, you can divide the 2 channel (R and L channel) stereo output become 4 channel output that are R channel, L channel, Center out and Rear out. This circuit will enrich your audio sound system.

For full explanation about this circuit, please visit this PAGE

3-3.5 Watt FM transmitter circuit

2009-05-08T23:29:00.000-07:00

This is 3-3.5 Watt FM transmitter circuit. With this power, it should be able to reach 3-5 KM distance. The frequency range is about 90-110 MHz.

Component list

Part	Total Qty.	Description
R1,R4,R14,R15	4	10K 1/4W Resistor
R2,R3	2	22K 1/4W Resistor
R5,R13	2	3.9K 1/4W Resistor
R6,R11	2	680 Ohm 1/4W Resistor
R7	1	150 Ohm 1/4W Resistor
R8,R12	2	100 Ohm 1/4W Resistor
R9	1	68 Ohm 1/4W Resistor
R10	1	6.8K 1/4W Resistor
C1	1	4.7pF Ceramic Disc Capacitor
C2,C3,C4,C5,C7,C11,C12	7	100nF Ceramic Disc Capacitor
C6,C9,C10	3	10nF Ceramic Disc Capacitor
C8,C14	2	60pF Trimmer Capacitor
C13	1	82pF Ceramic Disc Capacitor
C15	1	27pF Ceramic Disc Capacitor
C16	1	22pF Ceramic Disc Capacitor
C17	1	10uF 25V Electrolytic Capacitor
C18	1	33pF Ceramic Disc Capacitor
C19	1	18pF Ceramic Disc Capacitor
C20	1	12pF Ceramic Disc Capacitor
C21,C22,C23,C24	4	40pF Trimmer Capacitor
C25	1	5pF Ceramic Disc Capacitor
L1	1	5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L2,L3,L5,L7,L9	5	6-hole Ferroxcube Wide band HF Choke (5 WDG)
L4,L6,L8	3	1.5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L10	1	8 WDG, Dia 5 mm, 1 mm CuAg, Space 1 mm
D1	1	BB405, BB102 or equal (most varicaps with C = 2-20 pF [approx.])
Q1	1	2N3866
Q2,Q4	2	2N2219A
Q3	1	BF115
Q5	1	2N3553
U1	1	7810 Regulator
MIC	1	Electret Microphone
MISC	1	PC Board, Wire For Antenna, Heatsinks

Source: electronic-lab.com

Mini FM Transmitter

2009-05-08T20:30:00.000-07:00

Here the schematic diagram of mini and simple fm transmitter.

Supply voltage : 1.1 - 3 Volts
Power consumption : 1.8 mA at 1.5 Volts
Range : 30 meters max. at 1.5 Volts

Here the PCB Layout:

Visit this page for complete explanation

3 Line Mixer

2009-05-03T21:29:00.000-07:00

Actually, you can modify this circuit become more than 3 lines mixer. Just add and repeat the input parts (P=10K R=22K).

Schematic diagram:

Component placement:

PCB layout:

500 Watt Power Inverter

2009-05-01T19:25:00.000-07:00

Here the 500 Watt power inverter schematic diagram.

Click the image to get bigger size of schematic diagram and then save the image... or download the circuit diagram from here

Positive(+) to Negative(-) Voltage Inverter

2009-04-17T03:55:00.000-07:00

This simpe circuit will convert the positive input voltage become negative voltage.

Schematic diagram:

Component list:

Part	Total Qty.	Description
R1	1	24K 1/4 Watt Resistor
R2	1	56K 1/4 Watt Resistor
C1	1	3300pF 25V Ceramic Capacitor
C2	1	47uF 25V Electrolytic Capacitor
C3	1	10uF 25V Electrolytic Capacitor
D1, D2	2	1N4148 Silicon Diode
U1	1	555 Timer
MISC	1	Wire, Board

Notes:

V+ can be anywhere from 4 to 16V. -V is one volt less than V+. So for -12V output, use +13V input. The maximum current output of the circuit is about 280mA, more than enough for a few op amps.
For better regulation, a 79LOxx series regulator can be used.
A zener diode may also be used to regulate the output voltage.

3-30 V/2.5 A Adjustable Stabilized Power Supply

2009-04-10T02:15:00.000-07:00

This is Simple 3-30 volt adjustable and stabilized power supply circuit. You can use this circuit for general purpose.

Here the schematic diagram:

Component list:

R1 = 560R 1/4W	C1 = 100nF
R2 = 1,2 K 1/4W	C2 = 2200uF 35-40V
R3 = 3,9 K 1/4W	C3 = 100 pF
R4 = 15K 1/4W	C4 = 100uF/ 35V
R5 = 0,15R 5W

D = B40 C3300/2200, 3A rectifier bridge
P1 = 10K potesiometer	TR1 = BD 135
IC = LM723	TR2 = 2N3055

PCB layout:

Components placement:

For complete explanation, circuit's works and how to build this circuit into the box, download the full tutorial here

Universal Pre-Amplifier

2009-04-03T19:00:00.000-07:00

Here the universal pre-amplifier schematic diagram for common input device:

Download the schematic in PDF format

2 Way Cross-Over 3500 Hz (bass and treble)

2009-04-03T18:40:00.000-07:00

This is 2 way cross-over for your speaker system. This circuit will handle 2 speaker that are woofer (low frequency) an tweeter (high frequency).

The result will shown as below picture:

Here the schematic diagram of the circuit:

Visit this page for PCB layout and complete explanation about the circuit.

100W Audio Amplifier

2009-03-30T19:36:00.000-07:00

This amplifier comes with high fidelity (Hi-Fi), high sensitivity, low power consumption and low distortion. It will be nice for your high fidelity sound system. :)

Follow the instruction here

Dancing LEDs

2009-03-21T16:29:00.000-07:00

This is dancing LEDs schematic diagram. the LEDs will dance squence to audio (music or speaking) from the microphone.

Components list:

R1_____________10K 1/4W Resistor
R2,R3__________47K 1/4W Resistors
R4______________1K 1/4W Resistor
R5,R6,R7______100K 1/4W Resistors
R8____________820R 1/4W Resistor

C1,C3_________100nF 63V Ceramic or Polyester Capacitors
C2_____________10΅F 50V Electrolytic Capacitor
C4____________330nF 63V Polyester Capacitor (See Notes)
C5____________100΅F 25V Electrolytic Capacitor

D1___________1N4148 75V 150mA Diode
D2-D11_________5 or 3mm. LEDs (any type and color)

IC1___________LM358 Low Power Dual Op-amp
IC2____________4017 Decade counter with 10 decoded outputs IC

M1_____________Miniature electret microphone

SW1____________SPST miniature Slider Switch

B1_______________9V PP3 Battery

Clip for PP3 Battery

Additional circuit parts (see Notes):

R9,R10_________10K 1/4W Resistors
R11____________56R 1/4W Resistor

D12,D13 etc.____5 or 3mm. LEDs (any type and color)

Q1,Q2_________BC327 45V 800mA PNP Transistors
Q3____________BC337 45V 800mA NPN Transistor

Circuit operation:

IC1A amplifies about 100 times the audio signal picked-up by the microphone and drives IC1B acting as peak-voltage detector. Its output peaks are synchronous with the peaks of the input signal and clock IC2, a ring decade counter capable of driving up to ten LEDs in sequence.
An additional circuit allows the driving of up to ten strips, made up by five LEDs each (max.), at 9V supply. It is formed by a 10mA constant current source (Q1 & Q2) common to all LED strips and by a switching transistor (Q3), driving a strip obtained from 2 to 5 series-connected LEDs. Therefore one transistor and its Base resistor are required to drive each strip used.

Notes:

The sensitivity of the circuit can be varied changing R4 value.
C4 value can be varied from 220 to 470nF in order to change the circuit speed-response to music peaks.
Adopting the additional circuit, only one item for R10, R11, Q1 and Q2 is required to drive up to ten LED strips. On the contrary, one item of R9 and Q3 is necessary to drive each strip you decided to use.
Each R9 input must be connected to IC2 output pins, in place of the LEDs D2-D11 shown. R8 must also be omitted.
Whishing to use a lower number of LEDs or LED strips, pin #15 of IC2 must be disconnected from ground and connected to the first unused output pin. Example:
if you decided to use 5 LEDs, pin #15 of IC2 must be connected to pin #1; if you decided to use 8 LEDs, pin #15 of IC2 must be connected to pin #9 etc.
Current drawing of the circuit is about 10mA.
Whishing to use a wall-plug transformer-supply instead of a 9V battery, you can supply the circuit at 12V, allowing the use of up to 6 LEDs per strip, or at 15V, allowing the use of up to 7 LEDs per strip.

500W Inverter 12V DC to 220V AC

2009-03-15T19:36:00.000-07:00

This is inexpensive inverter circuit which able to convert 12V DC become 220V AC. IC CD4047 is use to generate the square wave of 50hz and amplify the current and then amplify the voltage by using the step transformer.

How to calculate transformer rating

The basic formula is P=VI and between input output of the transformer we have Power input = Power output

For example if we want a 220W output at 220V then we need 1A at the output. Then at the input we must have at least 18.3V at 12V because: 12V*18.3 = 220v*1

So you have to wind the step up transformer 12v to 220v but input winding must be capable to bear 20A.

60 Watt Amplifier using TDA2052

2009-03-12T19:14:00.000-07:00

This is HiFi audio amplifier system. This amplifier is AB class amplifier and has very low distortion that's why this amplifier can be used for HiFi audio system. TDA2052 has mute and st-by functions so it can be controlled by external digital circuits. Very high temperature and output short circuit protections are included. You should use a heatsink to dissipate the excess heat.

Functions of the Components:

R1 - Input Impedance
R2,R3 - Gain (32dB)
R4 - Input Impedance in Mute Mode
R5 - Standby Transition Time
R8 - Output Frequency Balancing
R9,R10 - Discharge Resistors
C1 - Input Coupling Capacitor
C3 - Feedback Coupling Capacitor
C4 - Standby Transition Time
C5 - Output Frequency Balancing
C6,C7 - Supply Stabilizing Capacitors
C9,C10 - Supply Filter Capacitors

Component List:

Component	Value	Number
R1,R2,R4,R5	11k ¼ W	4
R3	560, ¼ W	1
R6	7.5 K, ¼ W	1
R7	1 K, ¼ W	1
R8	4.7 , ¼ W	1
R9,R10	1.2 K, ¼ W	2
C1	2 uF/25 V	1
C3,C4	10 uF/25 V	2
C5,C9,C10	100 nF	3
C6,C7	1000 uF/40 V	1
U1	TDA2052	1

1.5 Watt FM Transmitter

2009-03-12T18:19:00.000-07:00

This is the the schematic diagram of 15 watt FM transmiter. The range should be 1-2Km with normal FM receiver.

Components List:

R1	220K
R2	4.7K
R3,R4	10K
R5	100ohm
C1,C2	4.7uF electrolytic
C3,C4	1nF
C5	2-15pF
C6	3.3pF
Q1	BC547C
Q2	2N2219A
P1	25K
MIC	ecm series

60W Power Audio Amplifier with 2N3055

2009-03-09T04:47:00.000-07:00

This circuit is simple and inexpensive:

This is a class B amplifier, this means, that a current must flow through the end transistors, even if there is no signal on the input. This current can be regulated with the 500Ω trimmer resistor. As this current incrases, the sound of the amplifier gets better, but the end transistors are more heating. But if this current decrases, the transistors are not heating so much, but the sound gets worse.

you can download the document version here

Infrared Modulation Identifier

2009-03-07T15:15:00.000-08:00

This is the schematic of Infrared Modulation Identifier Via Remote Control.

The circuit illustrates how the modulated carrier of infrared is measured by displaying the waveform on a frequency counter after the signal received is amplified.

More explanation, visit this page.

10 Band Graphic Equalizer

2009-03-04T17:12:00.000-08:00

This is 10 band graphic equalizer for one channel (mono) audio system. You need build 2 similiar circuits for 2 channel (stereo) audio system.

This equalizer build based on TL074 low noise JFET op-amp which will give you high quality audio output.

Part List

R1....20= 10Kohms	C4= 10nF polyester	C18= 68pF polysterine
R21....40= 1Mohms	C5= 47nF polyester	C19= 360pF polysterine
R41= 10Kohms	C6= 4.7nF polyester	C20= 36pF polysterine
R42= 1Kohms	C7= 22nF polyester	C21= 4.7uF polyester
R43.....52= 2.2Kohms	C8= 2.2nF polyester	C22-23= 33pF polysterine
R53.....62= 47Kohms	C9= 12nF polyester	C24= 10uF 25V
R63-64-66-67= 47Kohms	C10= 1.2nF polyester	C25-26= 47uF 25V
R65= 10Kohms	C11= 5.6nF polyester	C27...32= 47nF polyester
R68-69= 47 ohms 1/2W	C12= 560pF polysterine	IC1...3= TL074
RV1....10= 100Kohms lin FADER	C13= 2.7nF polyester	S1= 2X4 SW for stereo
RV11= 10Kohms log.	C14= 270pF polysterine
C1= 180nF polyester	C15= 1.5nF polyester
C2= 18nF polyester	C16= 150pF polysterine
C3= 100nF polyester	C17= 680pF polysterine

Multi Channel Audio Mixer using JFET 2N3819

2009-03-04T16:43:00.000-08:00

This is multi channel audio mixer using main component JFET 2N3819. You can add the input as many as you need for your project.

2N3819 is an n-channel JFET especially manufactured for RF and mixer applications and provides very low noise, very low distortion and excellent high frequency gain.