

Electronics Portable Organ
Most of the mechanical device is replaced by electronics circuit due to its portability, low cost, stable performance etc. Here is a simple project “Portable Electronics Organ” from single chip IC555 in order to replace the mechanical one. The circuit produces simple tones when the keys are pressed.
Circuit Description
The entire circuit of “Portable Electronics Organ” is build around Timer IC NE555 which is used in oscillator mode. The output is given to loudspeaker LS1 through DC blocking capacitor C1 from pin 2 (tone generator output). Resistor R2 through R6 and capacitors C2 determines the working frequency of the circuit. By selecting switch various tones can be generated. The preset VR1 is tuned to different notes and correct pitch by aural means, where reference notes is provides by pitch pipes or a tuned music instrument.

PART LIST
Resistors (all ¼-watt, ± 5% Carbon) |
R1 = 1 KΩ R2 = 1 KΩ R3 = 1 KΩ R4 = 1 KΩ R5 = 1 KΩ R6 = 1 KΩ R7 = 100 Ω VR1 = 20 KΩ variable type
|
Capacitors |
C1 = 10 µF/15V C2 = 0.1 µF or 100n Ceramic type C3 = 4700 µF , 15 V |
Semiconductors |
IC1 = LM7809 (9V Regulator IC) IC2 = NE555 D1 – D4 = 1N4002 LED1 = RED |
Its nice to see that you have updated the circut but i still have 1 question. There is a 4th capasitor in the circut that is not in he “part list”. I would like to know what the value of that capasitor is. Thank you!
Yeah , Thanks for your comments and I will also verify the previous circuit again and post it as a new project as soon as possible.
And the fourth capacitor ( which doesn’t have a number) is for voltage and current regulation so you can use a 4700 µF , 15 V capacitor.
Thank you for the answer. I guess i wont be needing that capacitor since im going to be driving this with a battery (replacing everything from the LM7809 and back).