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.

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

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

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

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

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

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

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

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.