SPACE_AGE_SOUND_MACHINE

Published:2009/6/18 22:55:00 Author:May | From:SeekIC

The space-age sound device uses a 556 dual-times IC to produce a phasor sound. That IC is ac-tually two 555 timer ICs in one 14-pin package, as shown in the schematic. Each timer inside the 556 is connected in an astable multivibrator mode.The first timer has its frequency set by R1, R2, and C1. Its output appears on pin 5 and it is cou-pled through C2 and R5 into the trigger input of the second timer. The second timer has an ad-justable frequency that is controlled by P1, R6, and C3.In the second timer, the first frequency mixes with the second frequency and produces the pha-sor-like sounds. The output of the second timer, which has the two signals mixed together, is brought from pin 9 through limiting resistor R7 to the input of Q1. The function of pnp gerrnanium power transistor Q1 is to amplify the signal to the level that is needed to drive the speaker. The green LED, L1, converts electrons directly into visible photons (light) in time with the pulses from the speaker. The purpose of resistor R8 is to limit the current through the LED to a safe level.



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