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This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED. The device must be placed a few centimeters from the cellular phone, so its sensor coil L1 can detect the field emitted by the phone receiver during an incoming call.... [read more]

This Power Supply is suitable for the Modular Burglar Alarm. However, it has other applications. It is designed to provide an output of 12-volts, with a current of up to 1-amp. In the event of mains failure, the back-up battery takes over automatically. When the mains is restored, the battery recharges.... [read more]

This circuit is design, in order to is heard the voice above the music. Useful for DJ, for small radio stations, for statements above the music, in shops etc. Also we can him use in applications that we want to handle some unit with our voice. As it has the circuit has become forecast for stereo music and monophonic microphone, but can be modified and be adapted in the needs or in the use that we want, him we use.... [read more]

This circuit is intended as a reliable replacement to thermally-activated switches used for Christmas tree lamp-flashing.... [read more]

This one uses a much more powerful "horse shoe" Xenon tube which produces more light. You can also control the flash rate up to about 20Hz. Do not look directly at the flash tube when this thing is on!... [read more]

The amplifier's gain is nominally 20 dB. Its frequency response is determined primarily by the value of just a few components-primarily C1 and R1. The values of the schematic diagram provide a response of ±3.0 dB from about 120 Hz to better than 20,000 Hz.Actually, the frequency response is ruler flat from about 170 Hz to well over 20,000 Hz; it's the low end that deviates from a flat frequency response.... [read more]