LIGHTENING DETECTOR

 LIGHTENING DETECTOR Clouds can carry such huge electric charges that may to cause lightning flashes of thousands of volts. It is really a fascinating phenomenon. When a lightning flash takes place a broad spectrum of radio-frequencies is generated. In this broad spectrum there is special intense emissions of the VLF (Very Low Frequency) band. This project will allow you to build a receiver to pick up a band near 300 KHz. An LED will flash to indicate the lightning flashes. THE CIRCUIT The radio-signal generated by the lightning flash is picked up by the telescopic antenna with the help of a 10mH choke. The choke L1 resonates with the antenna and allows current to flow into the receiver circuit. The L2 of 330uH in parallel with the 680pF capacitor C1 forms a tuned circuit for 300KHz. This parallel-tuned tank circuit is coupled to the base of Q1 via D2. The amplified radio signal is again coupled into the base of Q2. Transistors Q2 and Q3 form an LED flasher circuit. Transistor Q4 is the LED driver. The flasher is biased so that when VR1 is carefully adjusted the LED flashes only when a radio burst appears at the input due to a lightning flash. Positive feedback ensures the LED to be full on. The circuit quickly resets by charging C4 capacitor through diode D1. The circuit draws only about 100uA in idle state. Therefore it can run on two cells for many hours.

12v LAMP DIMMER

12v LAMP DIMMER Here is a 12 volt @ 2 amp lamp dimmer that can be used to dim a standard 25 watt bulb by controlling the duty cycle of a astable 555 timer oscillator. When the potentiometer is at the up position, the capacitor will charge quickly through both 1k resistors and the diode, producing a short positive interval and long negative interval which dims the lamp to near darkness. When the potentiometer is at the lower position, the capacitor will charge through both 1k resistors and the 50k potentiometer and discharge through the lower 1k resistor, producing a long positive interval and short negative interval which brightens the lamp to near full intensity. The duty cycle of the 200Hz square wave can be varied from approximately 5% to 95%. The two circuits below show how to connect the lamp to either the positive or negative side of the supply.

But the first circuit has a mistake and some components are not needed. The 555 will sink 300mA and it can be connected directly to the output transistor - you don't need the buffer transistor. When the 555 goes HIGH, the voltage on Pin 3 is 1.5v lower than the 12v rail and thus the transistor does not turn off. The two diodes in the circuit below are needed to drop an additional 1v so the transistor turns off.
 

10 OUTPUT LED SEQUENCER

 10 OUTPUT LED SEQUENCER Here is 10 output LED sequencer. After the last LED is illuminated, the circuit is reset. This circuit is build around readily available, low cost components - a 555 and decade counter CD4O1 7. The timer IC NE555 is wired as an astable multivibrator that produces 6Hz clock at its output pin 3. The 4017 is a CMOS decade counter with 10 outputs. Inputs include a CLOCK (Pin 1 4), a RESET (Pin 15), and a CLOCK INHIBIT (Pin 13). The clock input connects to a Schmitt trigger for pulse shaping and allows slow clock rise and fall times (not needed in our case). The counter advances one output at the rising edge of the clock signal if the CLOCK INHIBIT line is low. A high RESET signal resets the counter to the zero output. The circuit may be configured for counts less than 10 by connecting RESET to an output pin (one after the desired count). Thus, a five stage sequencer can be made by connecting pin 15 to pin 1. A CARRY-OUT signal (pin 12) can be used to clock subsequent stages in a multi-device counting chain. The output from 1C2 pin 3 is connected to clock pin (pin 14) of the IC3 for sequencing operations. NPN transistors Q1- Q10 are used to increase the output current for the LEDs which is set by the common 150 ohm resistor. In the circuit, only one of the outputs is HIGH at any one time and the output advances by one count with every clock pulse.

REACTION TIMER GAME

  REACTION TIMER GAME 

 This is a game for two players. Player 1 presses the START button. This resets the 4026 counter chip and starts the 555 oscillator. The 555 produces 10 pulses per second and these are counted by the 4026 chip and displayed on the 7-Segment display. The second player is required to press the STOP button. This freezes the display by activating the Clock Inhibit line of the 4026 (pin 2). Two time-delay circuits are included. The first activates the 555 by charging a 10u electrolytic and at the same time delivering a (high) pulse to the 4026 chip to reset it. The second timer freezes the count on the display (by raising the voltage on pin 2) so it can be read.

TV REMOTE CONTROL JAMMER

 TV REMOTE CONTROL JAMMER This circuit confuses the infra-red receiver in a TV. It produces a constant signal that interferes with the signal from a remote control and prevents the TV detecting a channel-change or any other command. This allows you to watch your own program without anyone changing the channel !! The circuit is adjusted to produce a 38kHz signal. The IR diode is called an Infra-red transmitting Diode or IR emitter diode to distinguish it from a receiving diode, called an IR receiver or IR receiving diode. (A Photo diode is a receiving diode). There are so many IR emitters that we cannot put a generic number on the circuit to represent the type of diode. Some types include: CY85G, LD271, CQY37N(45¢), INF3850, INF3880, INF3940 (30¢). The current through the IR LED is limited to 100mA by the inclusion of the two 1N4148 diodes, as these form a constant-current arrangement when combined with the transistor and 5R6 resistor

tda7293

 

pir sansor

 

The ULN2003A/L and ULN2023A/L

HIGH-VOLTAGE, HIGH-CURRENT DARLINGTON ARRAYS

 deally suited for interfacing between low-level logic circuitry and multiple peripheral power loads, 

the Series ULN20xxA/L high-voltage, high-current Darlington arrays feature continuous load current ratings to 500 mA for each of the seven drivers.

 At an appropriate duty cycle depending on ambient temperature and number of drivers turned ON simultaneously,

 typical power loads totaling over 230 W (350 mA x 7, 95 V) can be controlled. Typical loads include relays, solenoids, stepping motors, 

magnetic print hammers, multiplexed LED and incandescent displays, and heaters. 

All devices feature open-collector outputs with integral clamp diodes. 

The ULN2003A/L and ULN2023A/L have series input resistors selected for operation directly with 5 V TTL or CMOS. 

These devices will handle numerous interface needs — particularly those beyond the capabilities of standard logic buffers. 

The ULN2004A/L and ULN2024A/L have series input resistors for operation directly from 6 to 15 V CMOS or PMOS logic outputs. 

The ULN2003A/L and ULN2004A/L are the standard Darlington arrays. 

The outputs are capable of sinking 500 mA and will withstand at least 50 V in the OFF state. 

Outputs may be paralleled for higher load current capability. The ULN2023A/L and ULN2024A/L will withstand 95 V in the OFF state. 

These Darlington arrays are furnished in 16-pin dual in-line plastic packages (suffix “A”) and 16-lead surface-mountable SOICs (suffix “L”).

 All devices are pinned with outputs opposite inputs to facilitate ease of circuit board layout. 

All devices are rated for operation over the temperature range of -20°C to +85°C. Most (see matrix, next page) are also available for operation to -40°C; to order, change the prefix from “ULN” to “ULQ”. FEATURES ■ TTL, DTL, PMOS, or CMOS-Compatible Inputs ■ Output Current to 500 mA ■ Output Voltage to 95 V

 ■ Transient-Protected Outputs 

■ Dual In-Line Plastic Package or Small-Outline IC Package

TDA2030 14 W hi-fi audio amplifier

 TDA2030 14 W hi-fi audio amplifier Features 

■ Wide-range supply voltage, up to 36 V

 ■ Single or split power supply 

■ Short-circuit protection to ground 

■ Thermal shutdown Description The TDA2030 is a monolithic integrated circuit in the Pentawatt® package

, intended for use as a low frequency class-AB amplifier.

Typically it provides 14 W output power (d = 0.5%) at 14 V/4 Ω. At ±14 V or 28 V, 

the guaranteed output power is 12 W on a 4 Ω load and 8 W on an 8 Ω (DIN45500).

 The TDA2030 provides high output current and has very low harmonic and crossover distortion. Furthermore, the device incorporates an original (and patented) short-circuit protection system comprising an arrangement for automatically limiting the dissipated power so as to keep the operating point of the output transistors within their safe operating range. A conventional thermal shutdown system is also included

Electrical specifications 

TDA2030 4/17 Doc ID 1458 Rev 3 d Distortion Po = 0.1 to 12 W,

 RL = 4 Ω, GV = 30 dB f = 40 to 15.000 Hz 0.2 0.5 % Po = 0.1 to 8 W, 

RL = 8 Ω, GV = 30 dB f = 40 to 15.000 Hz 0.1 0.5 % B Frequency response (–3 dB) Po = 12 W, 

RL = 4 Ω; GV = 30 dB 10 Hz to 140 Hz Ri Input resistance (pin 1) 0.5 5 MΩ Gv Voltage gain (open loop) 90 dB Gv Voltage gain (closed loop) f = 1 kHz 29.5 30 30.5 dB eN Input noise voltage B = 22 Hz to 22 kHz 3 10 µV i N Input noise current 80 200 pA SVR Supply voltage rejection GV = 30 dB; RL = 4 Ω, Rg = 22 kΩ, fripple = 100 Hz; Vripple = 0.5 Veff 40 50 dB I d Drain current Po = 14 W, RL = 4 Ω Po = 9 W, RL = 8 Ω 900 500 mA Tj Thermal shutdown junction temperature 145 °C

Making a Light Detector using LDR Circuit Diagram

 The above LDR Circuit Diagram works on the amount of light penetration. 

Hence, when it is completely dark, the LDR occupies high resistance. 

As a result, the voltage at the base of the transistor becomes too low to turn the transistor ON. 

At this stage, the current doesn’t flow from the collector to the emitter of the transistor, instead, it passes through the LDR and the potentiometer.   

When the light is provided at comparatively low density, the LDR has low resistance. 

But it is sufficient enough to bring the voltage at the base of the transistor higher and also to turn the transistor ON. 

Once the transistor is turned on, current starts flowing through it from the positive battery terminal to the negative battery terminal covering R1 and the LED. 

With this, the LED, lights up.     

 The equipment required to build the Light Detector Circuit includes resistor and LEDs. 

The former determines the amount of current that flows through the LED. 

An LED with 2V voltage drop gives a 7V voltage drop over the resistor when the transistor is ON and in general, 18 mA is considered as good current value for common LEDs.    

To power the circuit, a 9V battery is used and if any other battery is used, then the resistor value is changed to get the right amount of current flowing through the LED. 

To change the trigger point for the LED, the variable resistor is used, which examines the right amount of light for the LED to turn ON and OFF.

IC RADIO

 IC RADIO 

 This circuit contains an IC but it looks like a 3-leaded transistor and that's why we have included it here. The IC is called a 

"Radio in a Chip" and it contains 10 transistors to produce a TRF (tuned Radio Frequency) front end for our project. 

 The 3-transistor amplifier is taken from our SUPER EAR project with the electret microphone removed. The two 1N 4148 diodes produce a constant voltage of 1.3v for the chip as it is designed for a maximum of 1.5v. 

 The "antenna coil" is 60t of 0.25mm wire wound on a 10mm ferrite rod. 

The tuning capacitor can be any value up to 450p

6 to 12 WATT FLUORO INVERTER

 6 to 12 WATT FLUORO INVERTER 

This circuit will drive a 40 watt fluoro or two 20-watt tubes in series but with less brightness than 

the circuit above and it will take less current. 

 2 x 20 watt tubes = 900mA to 1.2A and 1 x 20 watt tube 450mA to 900mA depending on pot setting. 

The transformer is wound on a ferrite rod 10mm dia and 8cm long. 

The wire diameter is fairly critical and our prototype used 0.28mm wire for all the windings. 

Do not remove the tube when the circuit is operating as the spikes produced by the transformer will damage the transistor. 

The pot will adjust the brightness and vary the current consumption. 

Adjust the pot and select the base-bias resistor to get the same current as our prototype.

 Heat-sink must be greater than 40sq cm. Use heat-sink compound.

20 WATT FLUORO INVERTER

 20 WATT FLUORO INVERTER 

This circuit will drive a 40 watt fluoro or two 20- watt tubes in series. 

 The transformer is wound on a ferrite rod 10mm dia and 8cm long. 

 The wire diameters are not critical but our prototype used 0.61mm wire for the primary and 0.28mm wire for the secondary and feedback winding. 

 Do not remove the tube when the circuit is operating as the spikes produced by 

the transformer will damage the transistor. The circuit will take approx 1.5amp on 12v, making it more efficient than running the tubes from the mains. 

A normal fluoro takes 20 watts for the tube and about 15 watts for the ballast