Mini FM Transmitter Circuit Diagram

This is a some what powerful transmitter.Here I have used famous Transistor 2N2222.This circuit operates with 3V power supply.To make L1 wind 5 turns of 24AWG wire on a 1cm plastic former.

[Continue reading...]

Mini High Voltage Generator Circuit

Here’s a project that could be useful this summer on the beach, to stop anyone touching your things left on your beach towel while you’ve gone swimming; you might equally well use it at the office or workshop when you go back to work. In a very small space, and powered by simple primary cells or rechargeable batteries, the proposed circuit generates a low-energy, high voltage of the order of around 200 to 400 V, harmless to humans, of course, but still able to give a quite nasty ‘poke’ to anyone who touches it.

Quite apart from this practical aspect, this project will also prove instructional for younger hobbyists, enabling them to discover a circuit that all the ‘oldies’ who’ve worked in radio, and having enjoyed valve technology in particular, are bound to be familiar with. As the circuit diagram shows, the project is extremely simple, as it contains only a single active element, and then it’s only a fairly ordinary transistor. As shown here, it operates as a low-frequency oscillator, making it possible to convert the battery’s DC voltage into an AC voltage that can be stepped up via the transformer.

Using a centre-tapped transformer as here makes it possible to build a ‘Hartley’ oscillator around transistor T1, which as we have indicated above was used a great deal in radio in that distant era when valves reigned supreme and these was no sign of silicon taking over and turning most electronics into ‘solid state’. The ‘Hartley’ is one of a number of L-C oscillator designs that made it to eternal fame and was named after its invertor, Ralph V.L Hartley (1888-1970). For such an oscillator to work and produce a proper sinewave output, the position of the intermediate tap on the winding used had to be carefully chosen to ensure the proper step-down (voltage reduction) ratio.

Here the step-down is obtained inductively. Here, optimum inductive tapping is not possible since we are using a standard, off-the-shelf transformer. However we’re in luck — as its position in the centre of the winding creates too much feedback, it ensures that the oscillator will always start reliably. However, the excess feedback means that it doesn’t generate sinewaves; indeed, far from it. But that’s not important for this sort of application, and the transformer copes very well with it.

The output voltage may be used directly, via the two current-limiting resistors R2 an R3, which must not under any circum-stances be omitted or modified, as they are what make the circuit safe. You will then get around 200 V peak-to-peak, which is already quite unpleasant to touch. But you can also use a voltage doubler, shown at the bottom right of the figure, which will then produce around 300 V, even more unpleasant to touch. Here too of course, the resistors, now know as R4 and R5, must always be present. The circuit only consumes around a few tens of mA, regardless of whether it is ‘warding off’ someone or not! If you have to use it for long periods, we would however recommend powering it from AAA size Ni-MH batteries in groups of ten in a suitable holder, in order not to ruin you buying dry batteries.

Circuit diagram:

Warning!
If you build the version without the voltage doubler and measure the output voltage with your multimeter, you’ll see a lower value than stated. This is due to the fact that the waveform is a long way from being a sinewave, and multimeters have trouble interpreting its RMS (root-mean-square) value. However, if you have access to an oscilloscope capable of handling a few hundred volts on its input, you’ll be able to see the true values as stated. If you’re still not convinced, all you need do is touch the output terminals...

To use this project to protect the handle of your beach bag or your attachecase, for example, all you need do is fix to this two small metallic areas, quite close together, each connected to one output terminal of the circuit. Arrange them in such a way that unwanted hands are bound to touch both of them together; the result is guaranteed! Just take care to avoid getting caught in your own trap when you take your bag to turn the circuit off!

 

 

Source by : Streampowers

[Continue reading...]

Let’s to build a mini organ keyboard circuit using UM3511

The previous
day my son said ” A friend has a mini organ. Casio SA-76 44 Key Mini
Keyboard, Orange It is Good quality but expensive.
My son would have
the same. But I said, as we are the Electronic inventor, to try to
create their own. We are proud and cheaper too.
You might like this
mini organ keyboard circuit certainly. Because in addition to the
simple, the price is not expensive, effective really worthwhile.
You may consider the main features of the circuit, as follows.
1. Can works with DC voltage in rang 3-12 Volt by low current consumption.
2. There are the music playback up to 15 keys, or a note from G3-G5.
3. Can be programmed to play. Repeat for up to 47 notes.
4. Can act as a music source by up to 15 songs.(Simple carbohydrates. Press any key. To select the desired song.)
How circuit works
In the heart of the circuit is the UM3511
-IC is designed to act this purpose

-Internal IC consists of a lot. We do not need to explain the
operation of the circuit Internal this IC. Our job only assembly
equipment used in the first the circuit to be completed.


-From circuit in figure 1 will see that we can connect a output of
pin 5 on the UM3511-IC to drive a transistor output to emit loud sound
out to the speakers directly.
-For the variable resistor-VR1 act as
determine a frequency of the oscillator circuit. When we created
successfully. Should be adjusted to the correct value. When adjusted,
you may use the normal resistor instead.
-The switch-S1 as an
option act the work of circuit that music will be played by the
application of the factory, or will play music as we have played own.
From pushing keyboard as by various notes.
For a list of songs that can be programmed from the factory. Which will play out as We have push switch as follows.
G3 Hush little baby
A3 Twinkle Little Star
C4 Dream of Home and Mother
D4 Christmas Carol
E4 Are You Sleeping
F4 The Famer in the Dell
G4 In a Persian Market
A4 Mary Had a Little Lamp
B4 Long Long Ago
C5 Santa Lucia
D5 Little Brown Jug
E5 Butterfly
F5 The Train is Running Fast
G5 Close Encounters of the Third Kind
How to build and setting
Suppose that you want to play Santa Lucia, it may be done as follows.
1. Hit the switch S1 to the program.
2. Press the C5 keyboard switch.
Only this time, it will play the music you want to finish it, it will stop automatically.

For convenience we have on the power supply is designed for the 5 volt
dc regulator circuit. To be applied to the input voltage from 6 volt to
24 volt. It also allows the voltage to be smooth, no hum at play.

Figure 2 the pcb layout of a mini organ keyboard circuit using UM3511
All components except the transformer and speaker. We can assemble onto the PCB. As shown in Figure 2.

For keyboard switch because we want you to get a feel for the playing.
As the organ of the fact that selling in the shop. We chose to use a
computer key switches.

[Continue reading...]

Pyle Mini stereo power amplifier

This mini stereo power amplifier provides up to 75 W of power on every channel by 4 ohms. unite your inputs using the RCA jacks. Outputs ended standard spokeswoman get behind jacks. It’s compatible with a few audio or else laptop device - you can even hook up an iPod using a 3.5mm to RCA jack converter. Treble, low, and volume controls on the front accede to you twist your sound to exactly how you aim it. Runs on 110 otherwise 220 vs..

The PCA3 mini stereo power amplifier from Pyle provides up to 75W of power on each one channel by 4 Ohms. link up your inputs using the RCA jacks, and output an better audio intimate done standard amplifier momentum jacks. It’s compatible with several audio before workstation device--you can even hook up an iPod using a 3.5mm to RCA jack converter. A master volume control on the front lets you adjust the get, and treble, deep, and volume controls on the front give permission you pull your sound to exactly how you be looking for it. The PCA3 runs on 110V or else 220V with a voltage selector switch.

[Continue reading...]