Wednesday, March 23, 2011

35W Audio Amplifier Circuit by STK082

Here is a 35W audio amplifier circuit built based on single Amplifier chip STK082. This is a very simple amplifier, very easy to build and produce sound output with a fairly large power of 35 watts into 8 Ohm loads.

35W Amplifier Circuit by STK082  Skema rangkaian STK082 - 35W audio Amplifier

STK082  icThis amplifier circuit is suitable for home power audio devices. The STK082 amplifier specifications might lead you to believe that it can use supply voltages of up to ±43V. but I don't recommend anything greater than ±25V if 8 ohm loads are expected, although ±30V will be fine if you can provide good heatsinking.


Rangkaian Audio Surround Decoder

This circuit has been created to design a decoder circuit that will operate in a module that would produce an audio surround sound.

Rangkaian Audio Surround Decoder Skema Rangkaian Audio Surround sound Decoder

The operation of the above circuits starts as the stereo sound signal transports surround sound information on the master volume part of the circuit. This will drive the Left channel Lch attached to Model TL072 IC1A and IC1b in which Right channel Rch is attached. The outputs on these operational amplifiers would serve as the input buffer to the following stages of the circuit. IC2C is responsible for summing up the signals from the left and right channels that will power the central loudspeaker output while IC2D is responsible for increasing the phase difference between left and right channels which is encoded in the two channels and will be fed to the rear loudspeakers. It is necessary to ensure that the negative terminals between the rear speaker is not earthed because they will simply function in parallel with the main speakers.

The output of IC2D will power regulated delay unit of audio to the rear loudspeakers. This would lead to the creation of proper sense of spacing in accordance to the size of the room. This will incorporate op-amp sound delay signal IC5 MN3004 which has 512 stages. Since IC4 MN3101 is a clocking signal, it provides timing to IC5 as it functions as an oscillator in the circuit. Variable capacitor C17 regulates the delay time in the circuit. The presence of filters in the circuit is for the purpose of preventing noise that will be produced during the process. These filters can be regulated to cut the frequencies above 8 KHz and under 100 Hz, to be able to drive the rear speaker. The rear loudspeaker is small in size because its input is encoded with a bandwidth of 100 Hz up to 8 KHz. The filters are built around the IC6A/B which is also an output buffer. A potentiometer is placed in every output to aid in the adjustment and regulation of loudspeakers and amplifiers. The supplied power in the circuit is 15 V and every output can drive a single power amplifier.

List Compoment
R1-2-7-8-12-13-18-19-20 : 47Kohm
R3-4-5-6-21-22-34-35 : 10Kohm
R9-10-11-14-15-16-17 : 15Kohm
R23-24-25-33-36 : 100ohm
R26-27-28-31-32 : 100Kohm
R29-30 : 5.6Kohm
C1-8 : 47uF/25V
C2-7-9-14-23 : 47nF
C3-6 : 1uF/100V
C4-5-10 : 33pF
C11-12-15 : 10uF/25V
C13 : 82nF
C16 : 18pF
C17 : 100pF mini adjustable capacitor
C18 : 2.2nF
C19 : 4.7uF/25V
C20 : 100nF
C21 : 10nF
C22 : 180pF
C24 : 150nF
RV1-RV2 : 2 X 10Kohm Log. pot.
RV3-4 : 10K Log pot.
D1 : 1N4148
IC1-6 : TL072
IC2-3 : TL074
IC4 : MN3101
IC5 : MN3004

This Audio Surround Decoder circuit from


Rangkaian Charger aki 6 Volt

Here is the circuit diagram of a low cost charger for 6 volt batteries. This circuit requires a regulated 10V-DC front end capable of supplying 2 Amps. Begins the charge period at 240mA and at full charge switches automatically to a float condition of 12mA. The capacitors should be the electrolytic 25V or greater.

Rangkaian Charger aki 6 VoltSkema Rangkaian Charger aki 6 Volt
Switching transistor T1 is an TIP31C NPN transistor, Si-Power Output/SW, with a TO-220 case and can be changed by using a appropriate substitute such as the NTE291, ECG291, etc. Timer/Oscillator U1 is a 8-pin NE555V and can be changed with a NTE955M or ECG955M. Resistors R4, R5, R6, and R7 are 1% metal film types.


100Watt Inverter Circuit by IRF44 Mosfet

This inverter circuit will provide a very stable 230V Output Voltage. Frequency of operation is determined by a VR1 and is normally set to 60 Hz. Various “off the shelf” transformers can be used. Or Custom wind your own for best results. Additional MosFets can be paralleled for higher power. It is recommended to Have a “Fuse” in the Power Line and to always have a “Load connected”, while power is being applied. The Fuse should be10 Amps per 100 watts of output. The Power leads must be heavy enough wire to handle this High Current Draw

100Watt Inverter Circuit by IRF44 MosfetSkema Rangkaian 100Watt Inverter by IRF44 Mosfet


Absolute Maximum Ratings of IRF44 Mosfet
  • Continuous Drain Current (25°C, 10V) = 49 A
  • Continuous Drain Current ( 100°C, 10V) = 35 A
  • Pulsed Drain Current = 160 A
  • Power Dissipation = 94 W
  • Gate-to-Source Voltage = ± 20 V
  • Avalanche Current = 25 A
  • Operating Junction = -55 to + 175


Monday, March 07, 2011

12VDC to 220VAC Inverter Circuit Using IC 555

This is a simple 12VDC to 220AC inverter circuit that can be used produces an AC output at line frequency and 220AC or different voltage by selecting transformer T1. The 555 IC is configured as a low-frequency oscillator, tunable over the frequency range of 50 to 60 Hz by Frequency potentiometer R4.

12VDC to 220VAC Inverter Circuit 12VDC to 220VAC Inverter Circuit

The 555 feeds its output (amplified by Q1 and Q2) to the input of transformer T1, a reverse-connected filament transformer with the necessary step-up turns ratio. Capacitor C4 and coil L1 filter the input to T1, assuring that it is effectively a sine wave. Adjust the value of T1 to your voltage. The output ( in watts) is up to you by selecting different components.

Input voltage is anywhere from +5V to +15Volt DC, adjust the 2700uF cap's working voltage accordingly. Replacement types for Q1 are: TIP41B, TIP41C, NTE196, ECG196, etc. Replacement types for Q2 are: TIP42B, TIP42C, NTE197, ECG197, etc.


Friday, March 04, 2011

Smoke Detector circuit Using LDR

This is a simple Smoke Detector circuit based on a LDR and lamp pair for sensing the fire. It uses a very simple approach to detecting smoke in the air. The alarm works by sensing the smoke produced during fire. The circuit produces an audible alarm when the fire breaks out with smoke.
Smoke Detector circuitSmoke Detector circuit using LDR

When there is no smoke the light from the bulb will be directly falling on the LDR.The LDR resistance will be low and so the voltage across it (below .6V).The transistor will be OFF and nothing happens. When there is sufficient smoke to mask the light from falling on LDR, the LDR resistance increases and so do the voltage across it.Now the transistor will switch to ON.This gives power to the IC1 and it outputs 5V.This powers the tone generator IC2 to play a music.This music will be amplified by IC3 to drive the speaker.

The diode D1 and D2 in combination drops 1.4 V to give the rated voltage (3.5V ) to UM66 .UM 66 cannot withstand more than 4V.


Car Parking Sensor circuit Using Infra-Red LED

This circuit can be used for an assist in parking the car near the garage wall backing up Pls. LED D7 illuminates Pls bumper-wall distance is about 20 cm., D7 + D6 illuminate at about 10 cm. and D7 + D6 + D5 at about 6 cm. In this manner you are alerted Pls approaching too close to the wall.

Car Parking Sensor circuit Using InfraredCar Parking Sensor circuit

All distances mentioned before can vary, depending on infra-red transmitting and receiving LEDs used and are mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device sensitivity. Obviously, you can use this circuit in other applications like liquids level detection, proximity devices etc.

  • The infra-red Photo Diode D2, should be of the type incorporating an optical sunlight filter: these components appear in black plastic cases. Some of them resemble TO92 transistors: in this case, please note that the sensitive surface is the curved, not the flat one.
  • Avoid sun or artificial light hitting directly D1 & D2.
  • If your car has black bumpers, you can line-up the infra-red diodes with the (mostly white) license or number plate.
  • It is wiser to place all the circuitry near the infra-red LEDs in a small box. The 3 signaling LEDs can be placed far from the main box at an height making them well visible by the car driver.
  • The best setup is obtained bringing D2 nearer to D1 (without a reflecting object) until D5 illuminates; then moving it a bit until D5 is clearly off. Usually D1-D2 optimum distance lies in the range 1.5-3 cm.
List Component of Car Parking Sensor circuit:
R1             : 10K
R2,R5,R6,R9 : 1K
R3 : 33R
R4,R11 : 1M
R7 : 4K7
R8 : 1K5
R10,R12-R14 : 1K
C1,C4 : 1µF/63V
C2 : 47pF
C3,C5 : 100µF
D1 : Infra-red LED
D2 : Infra-red Photo Diode (see Notes)
D3,D4 : 1N4148
D5-7 : LEDs (Any color and size)
IC1 : NE555
IC2 : LM324
IC3 : LM7812

Skema Rangkaian Elektronika