Power Pulse Circuit Diagram



The LM350 is adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 3A over a 1.2V to 33V output range.This circuit requires 5-15V power supply.

Here is a VLF receiver tuned to 300 kHz designed to detect the crackle of approaching lightning. A bright lamp flashes in sychrony with the lightning bolts indicating the proximity and intensity of the storm. Figure 1 shows the simple receiver which consists of a tuned amplifier driving a modified flasher circuit.

The flasher is biased to not flash until a burst of RF energy, amplified by the 2N3904, is applied to the base of the 2N4403. The receiver standby current is about 350 microamps which is nothing at all to a couple of D cells, hardly denting the shelf life. Of course, the stormier it gets, the shorter the battery life.

Circuit diagram



For best effect, mount the lamp in an old-fashioned holder with an extra-large colored glass lense. Or construct your own fixture with a plate of textured colored glass behind a panel painted with black-crackle paint. Watch a few old science fiction movies for other ideas. A totally different approach is to mount the circuit in an empty glass jar with the antenna and bulb protruding through the top. (A malted-milk jar has a nice, red plastic lid which is easy to work and looks good.) Use a pin jack for the antenna.

The gadget looks quite home-made but fascinating. Boat owners may wish to replace the lamp with a 3-volt beeper to provide an early warning of approaching bad weather. Choose one of those unbreakable clear plastic jars like the large jars of coffee creamer. A little silicone rubber will seal the antenna hole in the lid of the jar. Use a longer antenna for increased sensitivity since there are few electrical noise sources on the lake.

Tune-up is simple: adjust the potentiometer until the regular flashing just stops. (Use a multi-turn trimmer.) When properly adjusted, the lamp will occasionally flash when large motors or appliances switch on and off and an approaching storm will give quite a show. Obviously, tune-up is a bit more difficult during stormy weather. Adjust the pot with no antenna if lightning is nearby. Tune an AM radio to the bottom of the dial to monitor the pulses that the lightning detector is receiving.

This lightning detector is not so sensitive that it will flash with every crackle heard on the radio but will only flash when storms are nearby. Increased sensitivity may be achieved by increasing the antenna length. The experienced experimenter may wish to add another gain stage after the first by duplicating the 2N3904 circuitry including capacitor coupling with the addition of a 47 ohm emitter resistor to reduce the gain somewhat.

This additional gain can cause stability problems if the layout is poor so novices are advised to use a longer antenna or adjust the sensitivity potentiometer more delicately instead! (When operating properly, the additional gain makes the pot adjustment much less critical.)

This simple ON OFF touch switch circuit is based on the well known timer IC 555 (IC1), which drives a relay that acts like a switch. The metal surfaces can have what form we want, but it should be clean and very close to the circuit.

Touch plate MP1 in order to close the contact of relay RL1 [ON], or plate MP2 in order to open the contact of RL1 [OFF]. The Led D2 turns on when the contacts of RL1 are closed. Two small pieces of metal can be used as sensor plates.

555 ON/OFF Touch Switch Schematic

Parts List
R1 = R2 = 3.3M
R3 = 10K
R4 = 1K
C1 = 10nF
D1 = 1N4007
Q1 = BC547
IC = NE555
12V relay

Circuit diagram :

Flashing Lights Schematic Circuit Diagram

Stairways, corridors or small indoor passages often tend to be dark throughout the day irrespective of the outdoor ambient light conditions. Therefore keeping such passages illuminated all the the time becomes imperative, however this leads to unnecessary wastage of electricity.

 An innovative way of solving this problem has been discussed in this article, by employing a clap operated momentary light switch circuit.

The circuit diagram may be understood as follows:

The idea is to switch ON the connected lights in the corridor through a  clap sound, whenever the involved passage is utilized.
The clap sound triggers the circuit and keeps the connected lights switched ON for a few seconds or until the predetermined time is lapsed, after which the lights are automatically switched OFF.

The configuration is actually a transistor based clap switch, but without a flip flop stage, rather the flip flop is replaced by a delay OFF timer stage for the necessary switching and sustaining of the lights for a fixed predetermined period.
The stage as usual includes a sound sensor stage consisting of a mic and the subsequent transistor amplifier stage using a couple BC547 transistors.

The next stage consists of the PNP transistor BC557 which receives the signals amplified from the first stage via the 47uF capacitor.
The fed signals are further amplified to much greater levels for triggering the final LED driver stage.
The LED driver stage consists of a group of white LEDs which provides enough light for illuminating a small passage premise.
The two 39K resistors and the 220uF capacitors form the basic delay OFF timer and decides for how many seconds the driver stage remains ON with the LEDs lit.

The power to the circuit can be either applied by incorporating a standard transformer/bridge AC/DC adapter or if the circuit needs to be more compact, a transformerless power supply may be included with the below shown circuit.

All the NPN transistors are BC547B and the single PNP transistor is a BC557B, LEDs are ordinary 5mm high efficiency white LEDs.

The coil can be of any type, a 100mH choke will also do, its introduced in order to keep the circuit stable and for avoiding self oscillations.