2×22W Stereo Car Audio Amplifier schematic diagram


This is a schematic diagram of stereo audio amplifier for your car. The circuit is powered by a single IC TDA1553 with some external components, this IC will handle your stereo car audio system.

2x22W Stereo Car Audio Amplifier circuit diagram

The TDA1553CQ is a monolithic integrated class-B output amplifier in a 13-lead plastic DIL-bent-SIL power package. It contains 2×22 W amplifiers in BTL configuration. The device is primarily developed for car radio applications.

The TDA1553CQ contains two identical amplifiers with differential input stages and can be used for bridge applications. The gain of each amplifier is fixed at 26 dB.

Special features of the device are:

3-state mode switch
· standby: low supply current (<100>

Loudspeaker protection
When a short-circuit to ground occurs, which forces a DC voltage across the loudspeaker of >= V, a built-in protection circuit becomes active and limits the DC voltage across the loudspeaker to <= V. Pin 12 detects the status of the protection circuit (e.g. for diagnostic purposes).

Short-circuit protection
If any output is short-circuited to ground during the standby mode, it becomes impossible to switch the circuit to the mute or operating condition. In this event the supply current will be limited to a few milliamps.

Download the TDA1553CQ datasheet

25W Power Amplifier based IC LM1875

Short circuit protection, 94dB supply rejection ratio, thermal protection, S/N ratio in excess of 100dB, Open loop gain typically 90dB and 70mA quiescent current, LM1875 is great enough to give you good audio performmance. This power IC will amplify the audio signal up to 30W output power.

25W Power Amplifier based IC LM1875

Component part list

R1 _____________ 1K
R2 _____________ 1M
R3 _____________ 22K
R4 _____________ 10K
R5 _____________ 180K
R6 _____________ 1R

IC1 ____________ LM1875
C1 _____________ 1uF 50V
C2,6 ___________ 100nF
C3 _____________ 22uF 63V
C4 _____________ 0.22uF
C7,5 ___________ 220uF 50V

Fuse holder & cover
2 amp fuses

Visit this 25W Power Amplifier page for detail explanation

Simple Gate Alarm

Here the simple gate alarm circuit that built based on CMOS IC 4093B. With CMOS IC, this circuit must be work with small universal power supply.
Simple Gate Alarm circuit diagram

IC1a is a fast oscillator, and IC1b a slow oscillator, which are combined through IC1c to emit a high pip-pip-pip warning sound when a gate (or window, etc.) is opened. The circuit is intended not so much to sound like a siren or warning device, but rather to give the impression: "You have been noticed." R1 and D1 may be omitted, and the value of R2 perhaps reduced, to make the Gate Alarm sound more like a warning device. VR1 adjusts the frequency of the sound emitted.

IC1d is a timer which causes the Gate Alarm to emit some 20 to 30 further pips after the gate has been closed again, before it falls silent, as if to say: "I'm more clever than a simple on-off device." Piezo disk S1 may be replaced with a LED if desired, the LED being wired in series with a 1K resistor.

Figure 2 shows how an ordinary reed switch may be converted to close (a "normally closed" switch) when the gate is opened. A continuity tester makes the work easy. Note that many reed switches are delicate, and therefore wires which are soldered to the reed switch should not be flexed at all near the switch. Other types of switches, such as microswitches, may also be used.

Spurce: http://www.zen22142.zen.co.uk/Circuits/Alarm/Galarm.html

High Frequency Waveform Generator schematic

This is a waveform generator based on IC with wide operating frequency, Maxim MAX038. This IC is able to generate frequency between 0.1Hz to 20MHz.

Here the schematic diagram:

High Frequency Waveform Generator circuit diagram

  • The circuit can be used to generate square wave, triangle, or sine wave by programming the pin inputs (A0:pin 3, A1:pin 4).
    • A0 A1 WAVEFORM
    • X 1 Sine wave
    • 0 0 Square wave
    • 1 0 Triangle wave
  • The frequency can be controlled using current. If we disconnect the 20k RIN from REF (pin 1) and connect it to a DAC, then we can control the frequency using microcontroller or digital interface. We can even control the chip using a quartz crystal (PLL) by controlling the current using a phase comparator output that compares the sync output (pin 14 of MAX038) and a reference clock from quartz crystal oscillator.

Just try to build this circuit... :)

Light Detector

This is a circuit diagram of light detector. This circuit can be used as a sensor of automatic lamp switch, thic circuit also can be used for anti theft alarm circuit.

Schematic diagram:
electronic circuit diagram

Use variable resistor R1 to adjust the light threshold at which the circuit triggers. R1's value is chosen to match the photocells resistance at darkness. The circuit uses a CMOS 4001 IC. Gate U1a acts as the trigger, U1b and c form a latch. S1 to reset the circuit. You may used piezo buzzer or LED as output indicator, you may use both of them.

Active FM Antenna Booster circuit

This is an active antenna booster. It's mean that the circuit require a power supply to be works.

Active FM Antenna Booster circuit

Input coil L1 consists of four turns of 20SWG enamelled copper wire (slightly space wound) over 5mm diameter former. It is tapped at the first turn from ground lead side. Coil L2 is similar to L1, but has only three turns. Pin configuration of transistor 2SC2570 is shown in the fm antenna booster schematic. Adjust input/output trimmers (VC1/VC2) for maximum gain.

High Quality Intercom circuit

This is an intercom circuit which use LM380 as the audio amplifier and 2 transistors as the microphone pre amplifier. The sound quality will be good enough with low cost building.
electronic circuit diagram

This circuit consists of two identical intercom units. Each unit contains a power supply, microphone preamplifier, audio amplifier and a Push To Talk (PTT) relay circuit. Only 2 wires are required to connect the units together. Due to the low output impedance of the mic preamp, screened cable is not necessary and ordinary 2 core speaker cable, or bell wire may be used.

Detail explanation about this intercom circuit include the PCB layout, please visit this page

Stereo Tone Control circuit


This is stereo tone control circuit based on IC LM1036. The circuit should be works with supply voltage 9V to 15V DC.

Stereo Tone Control circuit

And here the circuit's features:

  • Wide supply voltage range, 9V to 16V
  • Large volume control range, 75 dB typical
  • Tone control, ±15 dB typical
  • Channel separation, 75 dB typical
  • Low distortion, 0.06% typical for an input level of 0.3 Vrms
  • High signal to noise, 80 dB typical for an input level of 0.3 Vrms

Infrared Toggle Switch schematic diagram

Use this Infrared toggle switch for wireless switching. You need to add IR receiver to electronic device for switching using this circuit.

Infrared Toggle Switch schematic diagram


R8________________ 680R
R7, R9____________ 4K7
R1, R2, R4, R6____ 27K
R3________________ 100K
R5________________ 1M
C1, C2, C5________ 470nF
C3, C4, C6________ 47u/16v ecap
IC________________ 4013
Q2, Q3____________ BC548
Q1________________ BC558
D1________________ 1N4148
D2________________ 1N4004
ZD1_______________ Zener diode 5V6
IR receiver module
Miniature relay AZ-SH-112L

All modern IR remote control devices produce a continuous coded stream of pulses at 37.9 kHz when any button on the module is pressed. These IR pulses are detected and decoded by a receiver (your TV, VCR etc.) and the appropriate function activated. In our Kit the coded stream is converted into a single pulse and that single pulse is used to toggle a relay on & off. The coded information is lost. Only the fact that a button was pressed on your remote control unit is detected.

More about this Infrared Toggle Switch, download the manual

"Night Rider" 16 Stage Bi-Directional LED Sequencer circuit

This bi-directional LED sequencer circuit uses IC CD4516 and IC 74HCT138 as counter and decoder.

16 Stage Bi-Directional LED Sequencer circuit diagram

Circuit explanation:
The bi-directional sequencer uses a 4 bit binary up/down counter (CD4516) and two "1 of 8 line decoders" (74HC138 or 74HCT138) to generate the popular "Night Rider" display. A Schmitt Trigger oscillator provides the clock signal for the counter and the rate can be adjusted with the 500K pot. Two additional Schmitt Trigger inverters are used as a SET/RESET latch to control the counting direction (up or down). Be sure to use the 74HC14 and not the 74HCT14, the 74HCT14 may not work due to the low TTL input trigger level. When the highest count is reached (1111) the low output at pin 7 sets the latch so that the UP/DOWN input to the counter goes low and causes the counter to begin decrementing. When the lowest count is reached (0000) the latch is reset (high) so that the counter will begin incrementing on the next rising clock edge. The three lowest counter bits (Q0, Q1, Q2) are connected to both decoders in parallel and the highest bit Q3 is used to select the appropriate decoder.

source: http://www.qsl.net/yo5ofh/hobby%20circuits/led_circuits.htm

18W amplifier circuit based on IC HA13118


Here the 18W audio amplifier circuit which powered by IC HA13118 as the main component.The type of this amplifier is bridge amplifier since the output line does not grounded.

18W amplifier circuit based on IC HA13118

The supply voltage required for this circuit is 8 – 18V DC, at least 1 to 2 Amps. Maximum output power will only be obtained with a power supply of 18V at greater than 2 A, using a 4 ohm speaker. The power supply should be well filtered to reduce mains hum, a regulated supply will reduce noise even further. Extra filtering is unnecessary if operating from a battery supply.

View more explanation about this 18W audio amplifier circuit HERE.

16W Audio Amplifier with LM383 schematic diagram

Here the 16 watt power audio amplifier circuit powered by dual IC LM383. The single LM383 will amplify the input about 7-8 watt, dual IC should be gain up to 16 watt. You can use wide voltage range 5V - 20V to supply the power IC.
16W Audio Amplifier with LM383 schematic diagram
Component list:

U1, U2____________ LM383 power IC
R1, R3____________ 220 Ohm resistor
R2, R4____________ 2.2 Ohm resistor
R5________________ 1 MegaOhm resistor
R6________________ 100k potentiometer
C1, C7____________ 10uf electrolytic capacitor
C2, C5____________ 470uf electrolytic capacitor
C3, C4, C6________ 0.2uf ceramic capacitor
SPKR1_____________ 4 to 8 ohm speaker (up to 8 inches diameter)

10 Watt Amplifier with TDA2009A Schematic Diagram

This is schematic diagram of 10 watt power audio amplifier using TDA2009A as the main component.
10 Watt Amplifier with TDA2009A Schematic Diagram

Component list:

R1, R3_________ 1K2 ohm
R2, R4_________ 18 ohm
R5, R6_________ 1 ohm
C1, C2_________ 3u3 50V mini
C3_____________ 22uF 16V
C5_____________ 100uF 35V
C6, C7_________ 220uF 10V
C10, C11_______ 2200uF 35V
C4, C8, C9_____ 100nF
IC_____________ TDA2009A
Heat sink
Download 10 Watt Amplifier with TDA2009A Schematic Diagram in PDF version HERE

Preamp + Tone Control Circuit

This is a preamp and tone control which combined in in one circuit.
P1 to control the volume level, P2 to control Bass level and P3 to control Treble level.
Preamp + Tone Control Circuit

This is a mono channel circuit, build another equal circuit to make this circuit stereo.



C1,C2,C9____470nF 63V Polyester Capacitors
C3,C4_______47nF 63V Polyester Capacitors
C5,C6_______6n8 63V Polyester Capacitors
C7__________10µF 63V Electrolytic Capacitor
C8,C10______22µF 25V Electrolytic Capacitors
C11_________470µF 25V Electrolytic Capacitor

Q1,Q3_______BC550C 45V 100mA Low noise High gain NPN Transistors
Q2__________2N3819 General-purpose N-Channel FET

100W Power Amplifier for Guitar

100 Watt Guitar Amplifier

This is a 100 watt audio power amplifier circuit for your guitar. Of course a high quality pre-amp is needed to produce high quality audio output.

You need this schematics..? Go to THIS page and you will find a good pre-amp and power amplifier for your guitar include the complete explanation of its works, and how to build the box.

Low-Ripple Power Supply

Low-Ripple Power Supply circuit diagram

This circuit can be used where a high current is required with a low-ripple voltage (such as in a high-powered class AB amplifier when high-quality reproduction is necessary). Q1, Q1 and R2 can be regarded as a power Darlington transistor. ZD1 and R1 provide a reference voltage at the base of Q1. ZD1 should be chosen thus: ZD1=Vout-1.2 . C2 can be chosen for the degree of smoothness as its value is effectively multiplied by the combined gains of Q1/Q2, if 100uF is chosen for C2, assuming minimum hfe for Q1 and Q2, C=100x15(Q1)x25(Q2)=37,000uF.

DC to DC Converter Multi Output

electronic circuit diagram

This circuit will convert DC volt input +9 to +16 DC Volt.
Output will be:
+28V DC
+15V DC
-5V DC
-12V DC

Simple Touch Switch

With touch switch, you can turn on and turn on a electronic device. Touch switch don't need mechanical part, so they will not worn out due to mechanical contact. Touch switches can be used in places where regular switches would not last, such as wet or very dusty areas.

Here the schematic diagram:
Simple Touch Switch circuit diagram

Component part list:

Part Total Qty. Description

C1 1 10uF 16V Electrolytic Capacitor
R1, R2 2 100K 1/4 Watt Resistor
R3 1 10 Meg 1/4 Watt Resistor
U1 1 4011 CMOS NAND Gate IC
MISC 1 Board, Wire, Socket For U1


1. The contacts an be made with just two loops of wire close together, or two squares etched close together on a PC board.

2. When activated, the output of the circuit goes high for about one second. This pulse can be used to drive a relay, transistor, other logic, etc.

3. You can vary the length of the output pulse by using a smaller or larger capacitor for C1.

Sine Wave Generator (1KHz Frequency)

This is iKHz sine wave generator circuit built based on configuration of inverted Wien bridge (see C1-R3 & C2-R4). R5 and R7 used for output amplutide setting. Set R5 to read 1V RMS on an Audio Millivoltmeter connected to the output with R7 rotated fully clockwise, or to view a sinewave of 2.828V Peak-to-Peak amplitude on the oscilloscope.
Sine Wave Generator circuit diagram

Component list:
R1____________5K6  1/4W Resistor
R2____________1K8 1/4W Resistor
R3,R4________15K 1/4W Resistors
R5__________500R 1/2W Trimmer Cermet
R6__________330R 1/4W Resistor
R7__________470R Linear Potentiometer

C1,C2________10nF 63V Polyester Capacitors
C3__________100µF 25V Electrolytic Capacitor
C4__________470nF 63V Polyester Capacitor

Q1,Q2_______BC238 25V 100mA NPN Transistors
LP1___________12V 40mA Filament Lamp Bulb (See Notes)
J1__________Phono chassis Socket
SW1__________SPST Slider Switch
B1_____________9V PP3
Clip for 9V PP3 Battery


  • The bulb must be a low current type (12V 40-50mA or 6V 50mA) in order to obtain good long term stability and low distortion.
  • Using a bulb differing from specifications may require a change of R6 value to 220 or 150 Ohms to ensure proper circuit's oscillation.
  • With C1, C2 = 100nF the frequency generated is 100Hz and with C1, C2 = 1nF frequency is 10KHz but R5 requires adjustment.
  • High gain transistors are preferred for better performance.

Audio Power Indicator

This is audio level indicator which can be used to measure the audio level output of your amplifier. Simply connect the output of your amplifier to the input of this circuit, then you will know the average value of your amplifier's power.
Audio Power Indicator circuit diagram

R1_____________220R  1/2W Resistor
R2,R5,R6,R8____100R 1/4W Resistors
R10,R12,R14____100R 1/4W Resistors
R3_____________220R 1/4W Resistor
R4,R7__________330R 1/2W Resistors
R9_____________560R 1/2W Resistor
R11____________820R 1/2W Resistor
R13______________1K2 1/2W Resistor

D1___________1N4004 400V 1A Diode
D2,D4,D6__BZX79C2V7 2.7V 500mW Zener Diodes
D3,D5,D7,D8,D9,D10 Red LEDs (Any dimension and shape) (See Notes)


  • The output power indicated by each LED must be doubled when 4 Ohms loads are driven.
  • The circuit can be adapted to suit less powerful amplifiers by reducing the number of LEDs and related voltage dividers.
  • LEDs of any dimension can be used, but rectangular shaped devices will be more suitable to be compacted in bars or columns.
  • For a stereo amplifier, two identical circuits are required.

70 Watt MOSFET Audio Amplifier

electronic circuit diagram

This amplifier circuit will give you about 70W output power at 60v supply.
Please visit this page for detail information and characterization

20W Bridge Audio Amplifier based on TDA2005

This is 20W Bridge Audio Amplifier circuit based on the TDA2005 IC, a class B dual audio amplifier, specifically designed for car radio applications etc.
This circuit require Voltage input 18 VDC and will give you Output power - 20 W, 4 Ω

This is the amplifier kit:
20W Bridge Audio Amplifier circuit diagram

This is the schematic:
20W Bridge Audio Amplifier circuit diagram

To get the schematic diagram, component list and component layout, please download this file

8 LED Audio Level Meter

This is 8 LED audio level meter circuit diagram. Build based on 2 pieces of op-amp IC LM324. You should use 4 ICs for stereo audio level meter.
Here the schematic:
8 LED Audio Level Meter circuit diagram

Running LED

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:
Running LED circuit diagram

And use this circuit use NAND logic:
Running LED circuit diagram

Zone Alarm System

electronic circuit diagram

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

Simple Electronic Buzzer circuit diagram

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

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

Variable Power Supply with L200 circuit diagram

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

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:
Power Audio Amplifier based on STK400xx  circuit diagram

Component Part list

R1-4 =1Kohm
R2= 33Kohm
R5= 0.22ohm 5W
R6=10ohm 2W
R7= 6,8ohm 2W
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
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

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

Digital Clock circuit diagram

Digital Clock circuit diagram

This is digital clock schematic diagram. This circuit is quite complex and quite difficult for a newbie because this circuit uses IC with some a complicated connections. The voltages that supplied to the circuit are divided in two lines.

Small Surround Sound Decoder

Small Surround Sound Decoder  circuit diagram

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

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.

FM transmitter circuit circuit diagram

Component list
PartTotal Qty.Description
R1,R4,R14,R15410K 1/4W Resistor
R2,R3222K 1/4W Resistor
R5,R1323.9K 1/4W Resistor
R6,R112680 Ohm 1/4W Resistor
R71150 Ohm 1/4W Resistor
R8,R122100 Ohm 1/4W Resistor
R9168 Ohm 1/4W Resistor
R1016.8K 1/4W Resistor
C114.7pF Ceramic Disc Capacitor
C2,C3,C4,C5,C7,C11,C127100nF Ceramic Disc Capacitor
C6,C9,C10310nF Ceramic Disc Capacitor
C8,C14260pF Trimmer Capacitor
C13182pF Ceramic Disc Capacitor
C15127pF Ceramic Disc Capacitor
C16122pF Ceramic Disc Capacitor
C17110uF 25V Electrolytic Capacitor
C18133pF Ceramic Disc Capacitor
C19118pF Ceramic Disc Capacitor
C20112pF Ceramic Disc Capacitor
C21,C22,C23,C24440pF Trimmer Capacitor
C2515pF Ceramic Disc Capacitor
L115 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L2,L3,L5,L7,L956-hole Ferroxcube Wide band HF Choke (5 WDG)
L4,L6,L831.5 WDG, Dia 6 mm, 1 mm CuAg, Space 1 mm
L1018 WDG, Dia 5 mm, 1 mm CuAg, Space 1 mm
D11BB405, BB102 or equal (most varicaps with C = 2-20 pF [approx.])
U117810 Regulator
MIC1Electret Microphone
MISC1PC Board, Wire For Antenna, Heatsinks

Source: electronic-lab.com

Mini FM Transmitter

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

Mini FM Transmitter circuit diagram

Here the PCB Layout:

Mini FM Transmitter circuit diagram

Visit this page for complete explanation

3 Line Mixer

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:
3 Line Mixer circuit diagram

Component placement:
3 Line Mixer circuit diagram

PCB layout:
3 Line Mixer circuit diagram

500 Watt Power Inverter

Here the 500 Watt power inverter schematic diagram.

Designed by: Syed Ashad Mustafa Younus
Revised by: Ronnie B. Tabanao

500 Watt Power Inverter circuit 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

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

Schematic diagram:
Positive(+) to Negative(-) Voltage Inverter circuit 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

  1. 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.
  2. For better regulation, a 79LOxx series regulator can be used.
  3. A zener diode may also be used to regulate the output voltage.

3-30 V/2.5 A Adjustable Stabilized Power Supply

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

Here the schematic diagram:
3-30 V/2.5 A Adjustable Stabilized Power Supply circuit 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:
3-30 V/2.5 A Adjustable Stabilized Power Supply circuit diagram

Components placement:
3-30 V/2.5 A Adjustable Stabilized Power Supply circuit diagram

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

Universal Pre-Amplifier

Here the universal pre-amplifier schematic diagram for common input device:
Universal Pre-Amplifier circuit diagram

Download the schematic in PDF format

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

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:
electronic circuit diagram

Here the schematic diagram of the circuit:
electronic circuit diagram

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

100W Audio Amplifier

electronic circuit diagram

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

Dancing LEDs circuit diagram

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.


  • 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.