Here’s a circuit for making your own flashing color party lights for Halloween (also called a color organ), you can pick up all the parts at RadioShack, assuming your local RadioShack is one of the ones that still has electronic parts… – “The following pictoral diagram illustrates how to wire the elements of a “direct connect” color organ, which uses 12 volt bulbs. Critical parts are listed as Radio-Shack part numbers. The power transformer will be the most expensive item (max. $10). Since this color organ uses half wave rectified voltage, a 25 volt transformer is used. A choice of power transformer is given since the “1366” has a capacity of 1.0 amp (at 12 volts), while the “1512” has a capacity of about 4.0 amps. This device is connected directly to any 8-ohm source of sound, such as the speaker output jack of any sound system.” [via] – Link.
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12 thoughts on “DIY Circuit – 1-Channel Light Organ for 12V Bulbs”
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So do the lights change indepently(loder sound more light come on)or all 3 lights pulse with beat of the music. I’m not sure put i want to guess my 2nd choice.
fw: sorry that should have been louder
A weakness of this design is its half-wave utilization. This condition leads to ‘core biasing,’ which has the unfortunate effects of unwanted heating of the transformer and reduction of its power capability. Two diodes could have been used to construct a ‘full wave center tap bridge rectifier’ to obviate this problem. Some bulbs (such as halogens) have a low resistance when cold, if these are the type one is using, inrush surge limiters can be of service.
A weakness of this design is its half-wave utilization. This condition leads to ‘core biasing,’ which has the unfortunate effects of unwanted heating of the transformer and reduction of its power capability. Two diodes could have been used to construct a ‘full wave center tap bridge rectifier’ to obviate this problem. Some bulbs (such as halogens) have a low resistance when cold, if these are the type one is using, inrush surge limiters can be of service.
Sorry about my prior double post. The lights will come on togeather as they are wired in shunt. When loads are in shunt, they form a current divider. The power consumed will be the sum of the rated power of the bulbs. The simplist way to make the bulbs switch at different levels of audio power would be to replicate the circuit and set the respective pots differently. This circuit is capable of supplying a marginal signal to the SCR, which can create EMI issues. An lpf followed by a comparator would obviate this problem, especially if buffered with a latch. In this case, choice of the lpf tc would allow frequency-selective responce.
The SCR part number 276-1067 is no longer available from Radio Shack. Is there a replacement you would recommend?