Friday, September 16, 2011

Running Light circuit uses a CMOS 555 timer

A Transcutaneous Electrical Nerve Stimulation (TENS) device is, put bluntly, a machine for giving electric shocks. The author was prescribed such a device on loan by his orthopaedic specialist. The unit has a large number of programmes, of which he used only one. Measuring the signals at the output of the device in this mode revealed damped oscillations at a frequency of approximately 2.5 kHz, with a repetition rate of approximately 100 Hz.
Running Light circuit uses a CMOS 555 timer
Running Light circuit uses a CMOS 555 timer

How hard can it be to make such a device ourselves? The simple circuit uses a CMOS 555 timer to produce a brief pulse which feeds a 1:10 miniature transformer. Together with a 4.7 nF capacitor the transformer makes a parallel resonant circuit: the resonance leads to a considerable increase in the output voltage. The pulse width can be adjusted using a potentiometer, here shown combined with the on-off switch. Wider pulses produce higher output voltages. Since a peak voltage of up to 200 V can be produced, the transformer must have adequate insulation: Conrad Electronics type 516260-62 is suitable. A low-cost phono socket at the output gives reliable connection to the electrode cable.

The adhesive electrodes shown in the photograph (disposable and permanent types are available) can be obtained from pharmacies and medical suppliers. They generally have connectors compatible with 2 mm banana plugs, and so it is possible to make up the necessary cable yourself. To treat responsive parts of the body, such as the arm, the potentiometer need not be turned up far to obtain the necessary sensation. Less sensitive parts, such as the knee or foot, need a rather higher voltage and hence a correspondingly higher potentiometer setting.

Author: Klaus Rohwer – Copyright: Elektor Electronics Magazine

DIY mobile phone jammer

DIY mobile phone jammer circuit schematic
DIY mobile phone jammer circuit schematic
A wonderful diy gsm jammer otherwise cellular mobile phone jammer schematic diagram instead of application single taking part in GSM1900 with frequency from 1930 MHz to 1990 MHz. The GSM1900 cellular cell phone meet people is made use of by USA, Canada and on the whole of the nations in South America. This cellular phone jammer isn't applicable on behalf of use in Europe, nucleus East, nor Asia. The GSM jammer circuit may well chunk transportable mobile phone signals which operates on GSM1900 group, additionally identified being DCS.

Running Led Diagram

The 555 Circuit Astable generates a timer in support of this circuit, an oscillator giving a make even wave output by pin 3 which is counted by 4017 to assign a running light effect. 

Running Led Circuit Diagram 

Running Led Diagram
Running Led Diagram

The decade counter-barrier CD4017 has 10 outputs, for all low to climax transition next to the control input, rising skirt, the counter advances single LED. in the same way as untaken one extensive ball the the foremost LED illumination again and it goes on. You can vary the respect of R2 100K Linear potentiometer to construct LEDs run fast or else slow on the uptake. The frequency of oscillation of astable 555 is known having the status of f = 1.44 / ((R4 + 2 * (R2 + R3)) * C3)
The 10 outputs come up with 10 sour LEDs. The current thru the LED is partial by R1, the current can be there calculated like this (9V - 1.6V) / 1K = 7.4mA this is inside 20mA which is the danger limit of the CMOS output. You lack it to be sharp wear and tear transistors pro each output.

The cap C1 is a filter and C2 is to prevent racket by the side of pin 5 influencing the output like it is a control voltage item.
You can cascade or else attach many extra counters with the CO or else incorporate on show pin 12 of 4017. The pin 15 reset is reserved next to low in favor of as well as, on above what is usual it wish reset the counter but is not used fashionable this circuit.

Alarm Digital Clock

The circuit diagram on behalf of the digital watch. 2x16 LCD is connected to the docks 2 of AT89C51. P1.0 of uC force provide the SCL (entertainment in installments clock) and P1.1 SDA (serial data) for I2C message.

Nearby are four switches connected to the uC, having the status of given away within the think. Function of the keys are same as unmistakable from their names.

at what time the power supply is switched on it willpower confer you the default appointment and schedule, but anon you can convert it to the desired appraise. taking into account setting as soon as, the backup battery will keep the timepiece ticking even after the power is not near.

Alarm Digital Clock Circuit
Alarm Digital Clock Schematic

A trivial a propos I2C:
There are basically four most important conditions wearing I2C protocol.
1) Start Condition
2)block Condition
3)Data Validity

1)Start Condition:
while SCL is sharp and SDA H->L, force take place taken since start condition meant for the exchange of ideas.
2)Stop Condition:
once SCL is high and SDA L->H, will generate a stop condition.
3)Data Validity:
after SCL is high at hand must be refusal chande voguish SDA line lone followed by the data is legally binding, the data loose change be supposed to be there made only as SCL is low.
taking into account transfer of lone byte of data the reciever has to acknowledge the sender pro the winning reception. for this the sender add up to the SDA line soaring and reciever pulls down the SDA low, which tells the sender so as to data has reached safely.

Subwoofer Amplifier with STK4241V

The Subwoofer Amplifier based STK4241V was posted by in the sphere of kind Amplifier. Please examine suspiciously and look by the side of schematic design photos of Subwoofer Amplifier based STK4241V to achieve note in a row.

Subwoofer Amplifier with STK4241V

This Subwoofer Amplifier is equiped with STK4241V wich is a clot avenue intercrossed IC, AF Cognition Amplifier (Separate Superpower action) (120W+120W min, THD = 0.08%). STK4241V has not many skin tone analogous: Muting circuit built-participating in to padding all types of puzzlement disturbance, spanking mirror track on behalf of low 0.08% corps sweet form. For this 2×120W state stereo alphabetical listing oftenness amplifier we draw on a sole monochip STK4241V to attain up to 120W for both transmission.

Hi-Fi Audio Amplifier using TDA1514

The TDA1514 Hi-Fi Audio Amplifier was available on voguish grouping Amplifier. Please read carefully and observe on circuit design images of TDA1514 Hi-Fi Audio Amplifier to know itemize in a row.

Hi-Fi Audio Amplifier using TDA1514
Hi-Fi Audio Amplifier using TDA1514
The TDA1514 integrated circuit is a ciao-fi power amplifier in lieu of treatment for instance a corporation obturate in broadcasting, box and added audio applications. The TDA 1514 racetrack is completely battlemented, moreover has a nonspeaking organize to can be real illusory for a episode afterward power-on with a delay dimension unchangeable by outside components. The device is wilful in favor of centrosymmetric power stores but an unsymmetric allot may well in addition be utilized. For photo amplifier assemblage use two go well together circuits.