Sound Activated Lamp.

This simple circuit shown int the schematic diagram actives the switch using sound. We can use this circuit for various applications, such as automatic (sound-controlled) disco light or car’s LED light show. The Q1 amplify the audio from mic. The R1 is used to adjust the peak of signal to greater than about 0.7 volts, act as sensitivity adjuster. A certain level, the signal coming from microphone, after amplification by Q1, will trigger the SCR and light lamp I1. If we change the lamp with a relay, then we can get a sound-activated relay/switch, which can be used to control more powerful / high wattage high voltage lamps. If we use a relay, place a 1N4007 diode in parallel with the relay coil to prevent the back-emf from relay coil destroying the SCR.

List Component :

R1 >> 1K

R2 >> 4.7K

R3 >> 1K

VR1 >> 5K

C1 >> 0.47 mf/16V

Q1 >> HEP802

SCR >> C103

20VAC 60 Watt Sunrise Lamp Circuit.

Download this schematic diagram.




Datasheet semiconductor component.

1. LM324
2. IRF640
3. IRF740

In this circuit, a 120VAC lamp is slowly illuminated over a approximate 20 minute period. The bridge rectifier supplies 120 DC to the MOSFET and 60 watt lamp. A 6.2K, 5 watt resistor and zener diode is used to drop the voltage to 12 volts DC for the circuit power. The bridge rectifier should be rated at 200 volts and 5 amps or more. In operation, a 700 Hz triangle waveform is generated at pin 1 of the LM324 and a slow rising voltage is obtained at pin 8. These two signals are compared at pins 12 and 13 to produce a varying duty cycle rectangular waveform at pin 14, which controls the MOSFET and brightness of the 60 watt lamp. When power is applied, the lamp will start to illuminate within a minute or so, and will slowly brighten to full intensity in about 20 minutes. You can make that longer or shorter with adjustments to the 270K resistor at pin 9. The 2.2 ohm resistor and .015uF cap connected to the lamp serve to supress RFI. The diode at pin 9 and 10K resistor on pin 8 are used to discharge the 3300uF cap when power is removed. Power should be off for a few minutes before re-starting.

Caution: This circuit is connected directly to the AC line and presents a hazard if any part is touched while connected to the line. Use caution and do not touch any parts while the circuit is connected to the AC line. You may want to use a 9 volt battery connected across the 12 volt zener to check the basic operation. The DC voltage at pins 1,2,3,5,6,7 will all be around 4.3 volts if the circuit is working correctly. If the DC voltages are all correct, you can use a variac to slowly apply the full line voltage and check for proper operation.

40 Watt Fluorescent Lamp Schematic Diagram.

Download this schematic diagram.





Download part list component.

The circuit works much like the original Strobos. except that a fluorescent tube is used. Thus, the fluorescent tube zündbereit remains constant, the two electrodes of the tube are continuously transformer Ta1 supplied with electricity. This current makes the two resistance wires of the glow tube in, so the mercury evaporates into the tube and the electron emission is simplified. Ta2 Returns on the rectifier “D1-D4 , the voltage of the multivibrator, the ignition frequency of the tube is responsible for. The speed of the AMV is with potentiometer P1 set. The pulse then passes through R3 to T3, is amplified there and controls the bias for the triac, the conducting of these alternates. If so, then the circuit through the tube and the ballast closes and the tube can light up. The pulses of T3 also enter via the capacitor C3 to the gate of the thyristor Th1. Simultaneously with the closing “of the circuit for the tube is Th1 -conductive and creates a short in the ignition coil current flow, which in turn generates a high voltage on the secondary. This voltage of several thousand volts is now operational on port J7 to a wire outside of the tube. The high voltage at the tube provides the necessary starting voltage so that it starts and can certainly light up until the thyristor Th1 locks again.

The points J1 and J2 to connect with the two electrodes on one side of the fluorescent tube. The points J3 and J4 , connect with the electrodes on the other side. Now stretch a thin insulated!! Wire along the tube and glue it eg. Scotch tape firmly. This wire carries the ignition voltage of several thousand volts to the tube so that they ignite properly. This wire, connect one end with J7 on the board, while the other end must necessarily be isolated. This wire leads except the high voltage pulses that is also voltage. The points with J5 and J6 of the board is one, tube fitting, ballast clamped to (choke, there’s the light trading.) Finally there is the voltage at J8 and J9. Now it should somehow already shine or flash, with the potentiometer, the flash rate can be set.

120 VAC Lamp Dimmer

The full wave phase control circuit below was found in a RCA power circuits book from 1969. The load is placed in series with the AC line and the four diodes provide a full wave rectified voltage to the anode of a SCR. Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF capacitor reaches about 8 volts, the transistors will switch on and discharge the capacitor through the SCR gate causing it to begin conducting. The time delay from the beginning of each half cycle to the point where the SCR switches on is controlled by the 50K resistor which adjusts the time required for the 2uF capacitor to charge to 8 volts. As the resistance is reduced, the time is reduced and the SCR will conduct earlier during each half cycle which applies a greater average voltage across the load. With the resistance set to minimum the SCR will trigger when the voltage rises to about 40 volts or 15 degrees into the cycle. To compensate for component tollerances, the 15K resistor can be adjusted slightly so that the output voltage is near zero when the 50K pot is set to maximum. Increasing the 15K resistor will reduce the setting of the 50K pot for minimum output and visa versa. Be careful not to touch the circuit while it is connected to the AC line.


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