Light/Dark Switch With Relay

The circuit as shown act as a light detector. Under normal conditions the resistance of the LDR is high, keeping pin 2 low. When light falls onto the LDR the resistance drops to a couple hundred ohms and triggers pin 2 high which biases the base of Q1 via pin 6 and R4 and in turn activates the relay.

Light/Dark switch Circuit with relay

As you may have notice, the 741 is connected as a voltage comparator. Two voltage dividers are easy to be found: The first one is the10K resistor and the LDR . The second one is composed by the two 470 Ohms resistors and the potentiometer. Both the outputs of the dividers are connected as inputs to the voltage comparator.

The second voltage divider will settle the reference voltage. The first voltage comparator that contains the LDR, will change it's voltage according to the light level. When the voltage across the negative input of the comparator is less than the voltage to the positive input of the comparator, the output is held low. When the voltage on the negative input rises, there will be a time that it becomes greater than or equal to the positive (pre-selected) voltage, and then the output becomes high and the relay through the 2N2222 is actuated.

Refrigerator Door Alarm Circuit Using LDR

The alarm circuit enclosed into a small box is placed in the refrigerator near the lamp. With the door closed the interior of the refrigerator is in the dark, the LDR R2 presents a high resistance thus clamping IC1 by holding pin 12 high. When a beam of light enters from the opening, or the refrigerator lamp illuminates, the LDR lowers its resistance, pin 12 goes low, IC1 starts counting and, after a preset delay (20 seconds in this case) the piezo sounder beeps for 20 sec. then stops for the same lapse of time and the cycle repeats until the refrigerator door closes. D2 connected to pin 6 of IC1 allows the piezo sounder beeping 3 times per second.

Skema Rangkaian Refrigerator Door Alarm Using LDR

Note:

• Delay time can be varied changing C1 and/or R3 values.
• Quiescent current drawing is negligible, so SW1 can be omitted.
• Place the circuit near the lamp and take it away when defrosting, to avoid circuit damage due to excessive moisture.
• Do not put this device in the freezer.

List Component:

R1    : 10K
r2    : LDR any type
R3,R4 : 100K
C1    : 10nF
C2    : 100µF/25V
D1,D2 : 1N4148
IC1   : 4060 14 stage ripple counter and oscillator IC
Q1    : BC337
BZ1   : Piezo sounder (incorporating 3KHz oscillator)
SW1   : SPST slide Switch
B1    : 3V Battery

This alarm circuit from : http://www.redcircuits.com/

Rangkaian 11-90 hz Subwoofer Filter Using TL072 Op-Amp

The subwoofer filter circuit allows the addition of subwoofers to an existing full-range system, offering adjustable low-pass filtering with optional R6 and R8 boost and mono-summing.

Skema Rangkaian 11-90 hz Subwoofer Filter
Using TL072 Op-Amp

TL072 Op-Amp

The Subwoofer filter circuit to remove for separate pre amplifier to drive the low frequency sound a lot. In tone, call tone, normal Can not be done … is a fine deep low bass sounds like a bass drum, or at a movie complex in a low voice if we can be heard with But to add cabinets and amps. The subwoofer circuit is pass low frequency with in 11-90 Hz. Switching power supply 12V cut out if they need to use +-15V. I had change the Capacitor to cut out vocals per the red circle mark.

6 Band Graphic Equaliser Circuit Using 741 Op-Amp

This circuit is 6 Band Graphic Equaliser ,you can adjust sound in low ,mid and high which circuit used IC 741 Op-Amp. With this circuit you can control and blend frequencies and tones as desired.

Essentially, the circuit consists of an IC 741 whose gain at various freguencies is determined by corresponding potentiometer setting.

Skema Rangkaian 6 Band Graphic Equaliser Using 741 Op-Amp

The audiblefrequency spectrum is covered in six steps: 50Hz, 160Hz, 500Hz, 1.6kHz, 5kHz, 16kHz. All potentiometers are of 100kΩ linear type. The circuit provides adequate boost / cut for normal use.

power supply for the circuit can be derived from the amplifier / preamplifier itself. The wide rangeof supply voltage (6V-20V) makes the circuit very versatile. Power consumption is negligible.

list Component

R1,R2,R3,R4,R5,R6 : 27kΩ     C1: 100n      C6: 300pF
R7:  470kΩ                   C2: 33n       C7: 100uF/16V
R8:  330kΩ                   C3: 10n       C8: 4.7uF/16V
R9:  100kΩ                   C4: 3.3n      C9: 47uF/16V
R10: 4.7kΩ                   C5: 1n        IC1: 741 Op amp
R11: 4.7kΩ
VR1,VR2,VR3,VR4,VR5,VR6: 100kΩ Linear Potentiometers 

Rangkaian 400W MOSFET Amplifier

These amplifiers circuit can be used for virtually any application that requires high performance, low use Noise, distortion and excellent sound quality. Examples would be subwoofer amplifier should FOH stage Amplifiers, surround a canal a very powerful sound amplifier, etc. The 400W MOSFET-amplifier has four key stages of amplification. We are looking to start any Phase appropriate detail.

Skema Rangkaian 400W MOSFET Amplifier

Note:

• Use + /-70V 10A DC dual supply for powering the circuit.
• For L1 make 12turns of enameled copper wire on a 1cm him: plastic formers.
• use 8 x IRFP448 MOSFETs in the final stages
• Heat sink is Necessary for the MOSFETs. A 8x4x4 inch finned aluminum heat sink will do. There is no such thing as a heat sink That is too large.

As the name suggests All Q ,C and ZD the Bias and buffer phases. Its main goal is to provide a stable MOSFET Gates and offset voltage and the voltage buffer amplifier stage of the High Resource capacity. What would have without the phase response and the effect Slew rate is indeed very bad. The flip side of the coin is not the extra step Introduction of an additional dominant pole in the amplifier feedback loop.

Also to what the name suggests this stage converts the voltage developed in the VAS and provides all the amps required to drive at 8 or 4 ohms. 2-ohm loads are possible for several minutes at a time. In fact, I have tested more than 1600 1kW amplifier Watts RMS at 2 ohms. But that would not be recommended as a long-term exposure at all. If it is higher than the figures of the STI-amp. Power to the AV amplifier 800 The components of the power for this amplifier are as follows, and are favored A channel or a power module alone. 1 toroidal transformer with a rating of 1kVA. Primary windings are made to fit

Audio Peak Level Indicator By Op-Amp

simple circuit PEAK indicator of foliage of the musical signal. This circuit was designed to provide a valuable test equipment tool for sound reinforcement systems like sound amplifiers and the like. The circuit is formed by an input buffer and ac to dc voltage converter (IC1A) feeding a window comparator (IC2A, IC2B, IC2C) which illuminates one of three LEDs at a time.

Skema Rangkaian Audio Peak Level Indicator By Op-Amp

No setup is required: if correct values are used for resistors R3 to R7, LED D1 will illuminate at 0dB input (0.775V RMS), LED D2 at +5dB input (1.378V RMS) and LED D3 at +10dB (2.451V RMS).

The circuit was optimized for low current consumption as it was intended for battery operation. To achieve this, the best arrangement has proven to be the one using two different op-amp types for IC1 and IC2. In fact the LM393 IC was not operating satisfactorily as dot-mode LED driver, whereas the LM324 was unable to charge C2 in the linear way, as expected. Therefore, the final circuit is some op-amp wasting, but the small added cost will be quickly compensated by battery savings.

List Component:

R1    : 300K         D1,D2,D3 : LEDs
R2    : 1M2          IC1      : LM393
R3    : 510K         IC2      : LM324
R4    : 220K         IC3      : 78L05
R5    : 91K          SW1      : SPST  Toggle or Slider Switch
R6    : 160K         B1: 9V  PP3 Battery
R7    : 56K
R8,R9 : 100R
R10   : 220R
C1    : 100nF
C2    : 1µF/63V
C3    : 10µF/25V