High Voltage Generator

This high voltage generator was designed  with the aim of testing the electrical break-down protection used on the railways. These  protection measures are used to ensure that  any external metal parts will never be at a  high voltage. If that were about to happen,  a very large current would flow (in the order  of kilo-amps), which causes the protection  to operate, creating a short circuit to ground effectively earthing the metal parts. This hap-pens when, for example, a lightning strike hits  the overhead line (or their supports) on the  railways.

This generator generates a high voltage of  1,000 V, but with an output current that is limited to few milliamps. This permits the electrical breakdown protection to be tested with-out it going into a short circuit state. The circuit uses common parts throughout: a  TL494 pulse-width modulator, several FETs or  bipolar switching transistors, a simple 1.4 VA  mains transformer and a discrete voltage multiplier. P1 is used to set the maximum current  and P2 sets the output voltage.

High Voltage Generator Circuit Diagram

The use of a voltage multiplier has the advantage that the working voltage of the smoothing capacitors can be lower, which makes them easier to obtain. The TL494 was chosen  because it can still operate at a voltage of  about 7 V, which means it can keep on working even when the batteries are nearly empty.  The power is provided by six C-type batteries, which keeps the total weight at a reason-able level.

The 2x4 V secondary of AC power transformer  (Tr1) is used back to front. It does mean that  the 4 V winding has double the rated voltage  across it, but that is acceptable because the  frequency is a lot higher (several kilo-Hertz)  than the 50 Hz (60 Hz) the transformer is  designed for. The final version also includes a display of the  output voltage so that the breakdown volt-age can be read.

From a historical perspective there follows a  bit of background information. In the past a different system was worked  out. Every high-voltage support post has a  protection system, and it isn’t clear when  the protection had operated and went into  a short-circuit state due to a large current  discharge.

Since very large currents were involved, a certain Mr. Van Ark figured out a solution for this.  He used a glass tube filled with a liquid containing a red pigment and a metal ball. When  a large current discharge occurred the metal  ball shot up due to the strong magnetic field,  which caused the pigment to mix with the liquid. This could be seen for a good 24 hours after the event. After a thunder storm it was  easy to see where a discharge current took  place: one only had to walk past the tubes  and have a good look at them.

Unfortunately, things didn’t work out as  expected. Since it often took a very long  time before a discharge occurred, the pigment settled down too much. When a dis-charge finally did occur the pigment no  longer mixed with the liquid and nothing was  visible. This system was therefore sidelined,  but it found its place in the (railway) history  books as the ‘balls of Van Ark’.

Author : By Jac Hettema – Copyright : Elektor

 

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Pulse generator circuit with Logic Gate

Pulse generator circuit above is a pulse generator that uses logic gates. There are so many types and variations that can generate a series of pulses.

The simplest is the use of transistors or often called a flip-flop. There also are using integrated circuit such as IC 555. Theres more to exploit the resonance of the capacitor and inductor relationship as oscillators. To be sure whatever form and whatever the circuit components used must be able to generate electric waves which have a peak voltage (logic 1) and valleys (logic 0) is continuous.

Any variation of pulse generator circuit design has advantages and disadvantages of each, just how your decision for the appropriate circuit. For example to create a clock signal for a simple utility that you can only take advantage of the transistor but if you need a more accurate clock signal and form a perfect balance you can use IC Astable or logic gates. Or perhaps you need a signal with very high frequency (up to MHz) you can use a combination of inductor, resistor and capacitor.

Frequency value of the pulse generator circuit gate above is determined by the value kapaitor C2, R2, R3 and VR2. The greater the value of these components will lower the frequency and vice versa. Actually nothing is difficult to make a series of pulse generators, almost all time-based series is utilizing the nature of the charge and discharge capacitor. Therefore, like any form of variations in pulse generator circuit, always have a larger capacitor value will make the frequency produced smaller or longer periods of time, sedangkaan smaller capacitor values ​​will result in greater output frequency.

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Metronome Generator using NE555

Here is a simple circuit using IC NE555 which will be used to generate metronomes.Such a circuit is incredibly helpful to people who learns music. The circuit is nothing however an astable multivibrator wired around NE555 .The elements|parts R1,R2&C1 determines the output frequency.

Notes.

• The circuit can be wired on a general purpose PCB or common board.
• The circuit can be powered from a 9V PP3 battery.
• The POT R1 can be used to adjust the rhythm of the sound.
• The POT R2 can be used as volume control.
• The speaker k1 can be a n 8 Ohm tweeter.

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Canary chirp generator

This is a simple electronic alarm schema that imitates the chirping of a canary. The schema is nothing but a Hartley oscillator with few more passive components added. As the capacitor C1 charges through the resistor R1 and the transistor Q1 is driven to cut off. This makes the oscillations to stop. As the capacitor discharges through the Resistor R1 and base emitter junction of the transistor the oscillation start again. Actually the R1 and C1 are the components that make the characteristic chirping sound.







Notes.

* Assemble the schema on a general purpose PCB.
* The schema can be powered from a 9V PP3 battery.
* The transformer T1 can be a audio output transformer like LT700.
* If LT700 is not available, try the audio output transformer used on you old transistor radio board.
* The speaker can be an 8 ohm tweeter.
* Switch S1 can be a push button switch.
* The chirping sound can be altered by changing the value of R1 and C1.

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Cricket Chirping Sound Generator

This is the schema diagram of cricket chirping sound generator based on IC 4060, a 14 stage ripple counter and oscillator IC. A suitable audio wave form is produced by IC2 and related electronic components, driving the mini speaker through Q1. To allow a more real-life behavior, the chirp is interrupted in a pseudo-casual way by two timers built around IC1C and IC1D, whose outputs are mixed into IC1B and further time-delayed by IC1A, driving the reset pin of IC2.

An optional Photoresistor can be wired across this pin and positive supply, it is to make the schema operates in the dark and stops when light is coming, thus imitating the crickets behavior even more closely. R9 acts as volume control and can be a preset trimmer or a small potentiometer.

Components List:

R1 = 330K 1/4W
R2 = 220K 1/4W
R3,R6 = 100K 1/4W
R4 = Photo resistor (Optional, see text)
R5,R7 = 22K 1/4W
R8 = 10K 1/4W
R9 = 470R 1/2W Trimmer Cermet or Carbon
R10 = 22R 1/4W
C1,C2,C3 = 47µF/25V
C4 = 10µF/25V
C5 = 1µF/50V
C6 = 10nF/63V
D1,D2,D3,D4 = 1N4148
Q1 = BC547
IC1 = 4093
IC2 = 4060
SPKR = 8 Ohm
SW1 = SPST Toggle or Slide Switch
B1 = 9V PP3 Battery (See Notes)

Circuit Notes:

• The schema can be powered by any battery or power supply adapter with 5 - 12V range.
• For maximum performance results please use a loudspeaker as small as possible.
• In some cases, the chirp can be improved further on by pressing the loudspeaker against a flat surface, for example. a wooden table.

Cricket chirping sound generator schema project, page source: extremediagram.net

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Simple Function Generator Wiring diagram Schematic

This is a simple function generator schema that can produce the following waveforms: square wave, triangular wave, and sine wave.

The diagram main components are two 1458 ICs.  The 1458 is a dual op-amp IC, i.e., an IC that houses two op amps inside it.  The schema uses four op amps, two from each 1458.

The bottom-most op amp in Figure 1 is configured as an astable multivibrator, which continuously generates a square wave.  Assume that C1 has no charge initially. The voltage at the inverting input is zero, while the voltage at the non-inverting input is very slightly positive (a ratio of the op amps output offset voltage as determined by R1 and R2). This minute voltage difference at the inputs is enough to cause the op amps output to swing to high.

When the output becomes high, C1 starts charging up. The voltage at the inverting input soon exceeds that at the non-inverting input, forcing the output to swing to low, which discharges C1 again.  At a certain point, the voltage at the non-inverting input exceeds that at the inverting input again, and the output of the op amp goes high again.

This cycle wherein the first op amps output swings between low and high goes on indefinitely, generating the square wave.

The two middle op-amps are both configured as integrators. The input to the second op amp is the square wave output of the first op amp.  Being configured as an integrator, this op amp outputs a triangular wave (the integral of a square wave), as shown in Figure 1. 

The triangular wave output of the second op amp is then fed into the third op amp, which is also configured as an integrator.  The output of the third op amp is a sine wave (the integral of a triangular wave).

The sine wave output of the third op amp is fed into the fourth op amp, which is configured as an inverting amplifier. The output of this last op amp is also a sine wave but opposite in phase as its input.

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NE 555 Pulse generator

Most of our members asked pulse generator diagram. so this is a simple and common schema.and you can use this with your light schema diagrams too.





Note

# Dont supply more than 15V

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Triangle Wave and Square Wave Generator

This is a simple schema diagram of triangle wave and square wave generator.



The schema is designed based on a common 1458 dual op-amp that can be used from very low frequencies to about 10 Khz. The time interval for one half cycle is about R*C and the outputs will supply about 10 milliamps of current. Triangle amplitude can be altered by adjusting the 47K resistor, and waveform offset can be removed by adding a capacitor in series with the output.

source of Triangle Wave and Square Wave Generator schema:
http://www.high-voltage-lab.com/211/triangle-squarewave-generator

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High Voltage DC Generator Wiring diagram Schematic

This schema is fed from a 12-V de power supply. The input to the schema is then amplified to provide a 10,000-Vdc output. The output of the up-converter is then fed into a 10 stage, high-voltage multiplier to produce an output of 10,000 Vdc.

High Voltage DC Generator Circuit Diagram

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PWM Generator Wiring diagram Schematic

PWM waveforms are commonly used to control the speed of DC motors. The mark /space ratio of the digital wave-form can be defined either by using an adjustable analogue voltage level (in the case of a NE555 based PWM generator) or digitally using binary values. Digitally derived PWM waveforms are most often produced by the timer/counter modules in microcontrollers but if you do not want to include amicrocontroller in your schema it’s also quite simple to generate the signals using discrete logic components. An extension of the schema shown can pro-duce two PWM waveforms from an 8-bit digital input word. Each signal has 15 val-ues. The 8-bit word can be produced for example from an expansion board fitted in a PC or from an 8-bit port of a processor which does not have built-in PWM capability or from a laptop’s printer port.

Discrete PWM Generator Circuit Diagram

The mark/space ratio is only programmable up to 15/16 rather than 16/16; a binary input of 0000 produces a continuous low on both outputs turning both motors off. Similar diagram often employ a dedicated ‘enable’ input to turn the motors off but it is not necessary in this design.

The diagram shows the schemary required to produce just one waveform. For the full two channel schema it is necessary to use an additional 74HC193. The clock signal produced by the HCF4060 generator can be used to drive both channels and the free flip flop in the 74HC74 package can be used for the second channel (the corresponding pin numbers are shown in brackets). Alto-gether the entire two channel schema can be built using just four ICs.

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