Free Simple Circuit Diagram
This touch tone decoder can be used to decode a DTMF (Dual Tone Multiple Frequency) signal from a telephone device or from other generator. Using the frequency values shown in the schematic diagram, this circuit decodes a standard touch tone codes. The components R1 and C1 for each 567 chip should be computed according to the formula: f=1/(1.1 *R1 *C1). […]
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The output of this circuit will be activated when a mix of two tone/frequency is detected on the input. The frequency f is determined by the values of R1 and C1, where f=1/(1.1 * R1 * C1). For security, using dual tone is more secure compared with using only single frequency. With single frequency, someone can easily find the secret […]
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Using 567 IC tone decoder/detector, we can build a remote control and or intercom. This circuit can be used to control a relay, or to carry an audio signal (intercom) through power-line wiring. Here is the schematic diagram of this remote control/intercom circuit: The relay will be activated if you inject a 100kHz tone. This can be used to control […]
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