shared wiring

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.

A two tone effect very much alike cuckoo sound is generated by this circuit. We can use this circuit for door-bells or other purposes thanks to a built-in audio amplifier and loudspeaker. Used as a sound effect generator, it can be connected to external amplifier, tape recorder, etc. The built-in audio amplifier and loudspeaker may be omitted and the output taken from C8 and ground in this case. There are two options: when SW1 is left open, we can use free running and when SW1 is closed we can use one-shot. A two-tone cuckoo sound will be generated each time P1 pushbutton is pressed in this case. This is the figure of the circuit;

IC1 is wired as a squarewave generator and two tones of cuckoo sound is produced by this IC. The frequency of the higher one (667Hz) is set by means of Trimmer R2. A further trimmer (R22) is added to IC1 timing components via D6, and the lower tone (545Hz) is generated when IC2D output goes low. The the squarewave output of IC1 is converted to a quasi-sinusoidal waveform by R3, R4, C3 and C4, then mixed with the white noise generated by Q1, R6 to imitate closely the cuckoo sound.Q2 has two purposes: it mixes the two incoming signals and gates the resulting tone, shaping its attack and decay behavior by means of the parts wired around its Emitter.

R15 is the volume control and IC4 is the audio power amplifier driving the speaker. The clock generator IC2A driving the decade counter IC3 provides the various sound and pause timings for the circuit. Some output pins of this IC are gated by IC2C, IC2D and related components to drive appropriately the sound generator and the sound gate. The circuit operates in the free-running mode and a cuckoo sound is generated continuously when SW1 is left open. the circuit generates two tones then stops, because a high state appears at the last output pin (#11) of the decade counter IC: therefore the count is inhibited by means of D1 feeding pin #13 when SW1 is closed. When P1 is pressed, the circuit is reset by a positive pulse at pin #15 of IC3. If the two tones frequencies are set precisely, the best result will be obtained. i.e. 667Hz for the first tone and 545Hz for the second (called Minor Third in musical terms). If available, a digital frequency would be the best tool to set up R2 and R22. You can use a musical instrument such as piano or guitar. Here’s the step to tuning-up the notes by musical instrument: First, we have to disconnect R22 from D6 diode temporarily then connect the digital frequency counter to pin 3 od IC1. To read 667Hz on the display, adjust R2 in order then connect R22 to negative ground and adjust it to read 545 Hz on the display and finally reconnect R22-D6.

Then, steps to tuning by ear: First, disconnect R22 from D6 anode temporarily. Disconnect C8 from Q2 Collector and connect it to R4, C4 and C5 junction. After that, adjust R2 in order that the tone generated by the loudspeaker is at the same pitch of the reference note generated by your musical instrument. This reference note will be the E written on the stave in the fourth space when using the treble clef. Then, Connect R22 to negative ground and adjust it in order that the tone generated by the loudspeaker is at the same pitch of the reference note generated by your musical instrument. This second reference note will be the C-sharp written on the stave in the third space when using the treble clef. Finally reconnect R22-D6 and C8-Q2 connections. For your note, the master clock can be adjusted by means of R18. The percentage of hiss and sound in the mixing circuit, setting the tone character, can be varied changing R8 and R7 values respectively. Any kind of dc voltage supply in the 12 – 15V range can be used, but please note that supply voltages below 12V will prevent operation of the white noise generator and an amusing application of this circuit is to use a photo-resistor in place of P1, then placing the unit near the flashing lamps of your Christmas tree. A sweet cuckoo sound will be heard each time the lamp chosen will illuminate.

The article explains an alternator power booster circuit which was unveiled by one of the keen followers of this blog, Mr Michael Mbamobi. Lets learn more about the details.


The email received from Mr.Michael:

Dear Swagatam, There is this circuit I want to show you. I want to show you the circuit through Homemade Circuit or Brighthub. I didnt see how I can upload picture there. Please direct me I can sent this through Homemade Circuit. Anyway I uploaded the picture here! see the circuit and find out what these our Nigerian Guys are up to. I only hear about this type of device here in Nigeria. I bought it and disassembled it. With your ability as Engr. Swagatam Majumdar, you can build a better device that can perform this same thing without depending on their own construction.

The folks call this an alternator power booster! It enables small gensets support loads bigger than their coils and feel alright with it without yearning!

I disassembled it carefully because D1, R1, R2, C2 and Q1 are obscured inside a glue like paste.

AC IN is from a small 650VA Generating set which is normally incapable of powering the connected loads.

The diode polarity and the value is not certain but this is its place in the circuit. It got broken while dismantling the glued circuit.

Q1 couldnt be traced either because the print was scraped of by the manufacture.Only its pin#1 and pin#3 responded to the DMM, it read zero like a dead diode, pin#2 does not read with any other pin at all. Pin#4 which is the tab is also unconnected.....just cannot figure out the device or its specs.

The diode D1 is blue in color, small glass type.



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