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.

500W Inverter 12V DC to 220V AC

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.
500W Inverter 12V to 220V circuit diagram

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

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.
60 Watt Amplifier using TDA2052 circuit diagram

Functions of the Components:

  1. R1 - Input Impedance
  2. R2,R3 - Gain (32dB)
  3. R4 - Input Impedance in Mute Mode
  4. R5 - Standby Transition Time
  5. R8 - Output Frequency Balancing
  6. R9,R10 - Discharge Resistors
  7. C1 - Input Coupling Capacitor
  8. C3 - Feedback Coupling Capacitor
  9. C4 - Standby Transition Time
  10. C5 - Output Frequency Balancing
  11. C6,C7 - Supply Stabilizing Capacitors
  12. C9,C10 - Supply Filter Capacitors

Component List:

Component Value
R1,R2,R4,R5 11k ¼ W 4
560, ¼ W 1
7.5 K, ¼ W 1
1 K, ¼ W 1
4.7 , ¼ W 1
1.2 K, ¼ W 2
2 uF/25 V 1
C3,C4 10 uF/25 V 2
100 nF 3
1000 uF/40 V 1
TDA2052 1

1.5 Watt FM Transmitter

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

Components List:

R1 220K
C1,C2 4.7uF electrolytic
ecm series

60W Power Audio Amplifier with 2N3055

This circuit is simple and inexpensive:

60W Power Audio Amplifier with 2N3055 circuit diagram

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

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

10 Band Graphic Equalizer circuit diagram
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

Multi Channel Audio Mixer circuit diagram

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.

6 Channels Audio Mixer

electronic circuit diagram
This is 6 Channel Audio Mixer circuit. 3 channel for microphone input and the others 3 channel for audio input like CD player, computer, or television. There will be 6 potensiometer to control the volume of each channel.

Dual Regulated Power Supply

electronic circuit diagram
This is dual regulated power supply. There are 3 output that are (+) voltage, (0) Grounding, and (-) voltage. The current output max about 0.3-0.5 A.

You need center tap transformer. for example, if you need 12v output, you should connect J1 to 15v transformer output, J2 connected to 0v and J3 connected to another 15V.

Electronic Fuse for DC Short Circuit Protection

Electronic Fuse for DC Short Circuit Protection circuit diagram

This circuit will protect your power supply or battery. The electric current will stopped by relay when electric current short occured, Relays must be chosen with a voltage value equals to the input voltage. Don't omit using the 100uF capacitor with appropriate voltage value with respect to the input voltage. If you can't provide, you can use C106 instead of BRX46.

You can adjust the current with using 10K potentiometer. If you will use the fuse with very high currents, lower the 0R6 5W resistor value (ex. 0R47, 0R33, 0R22 or 0R1). Watt value of the resistor should be increased also.