Using SFH505A integrated circuit manufactured by Siemens can be made a infrared triggered switch.
This switch has triggered by infrared light can be used to drive various electronic devices. IC1's output signal pulse width is limited to a maximum value.
Most commercial remote uses modulated data transfer pulse width which is smaller than that can work IC1. The difference is easily detected by an integrator, R2-C2, and a Schmitt trigger, monostable represented by T pin IC2a entry. Time constant is just so small as to ensure that the maximum pulse width of IC1, the voltage across C2 will be just below its switching threshold IC2a's (IC1 output is active "0", which is why connecting denied entry to trigger IC2a) .. Monostable pulse duration was set at about half a second. Therefore, the circuit can not connect or disconnect quickly a circuit.
Diode D2 indicates that IC2a has received a trigger signal.
The relays can switch up to 2000 VA (8 A).
Amps when connecting equipment may be limited connecting first supply voltage in series with a resistor through the first relay, and then using the second relay to remove the resistor circuit.
Circuit absorbs a current of about 0.6 mA when the relay is off and LED are off. The relays and LEDs powered on, it increases to 125 mA.
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