Showing posts with label relay. Show all posts
Showing posts with label relay. Show all posts
Friday, September 26, 2014
Build a Relay Switch Activated by Tone and Signal
The essence of the circuit is for the input of tone and signal to provide an activation for the relay switch.
- Relay – an electrically operated switch where the current flowing through the coil of the relay is creating a magnetic field which attracts a lever and changes the switch contacts, thereby making its state open or close
- BC214 – a complementary silicon planar epitaxial transistor used in AF small signal drivers and am1 as well as for low noise preamplifier applications due to its feature of good linearity of DC current gain
- LM741 – a general purpose single operational amplifier with features such as offset null, compensated internal freq uency, voltage range with high input, good stability of temperature, and protected from short circuit
The use of relay will allow the circuit to switch from one condition to another. It can also be referred to as a form of an electrical amplifier since it is able to control an output circuit of higher power than the input circuit. There are many types of relays being used in many electronic and electrical circuits, which include solid-state relay, Buchholz relay, overload protection relay, latching relay, forced-guided contacts relay, mercury-wetted relay, contactor relay, machine tool relay, reed relay, polarized relay, and solid state contactor relay.
The circuit created is sensitive enough to the AC signals in the input stage, where the signals are ranging above 5 mV. It will also be sensitive to react with the human voice signals having a range of frequency from 50 Hz up to 3 KHz. The human voice is a part of the human sound produced primarily by the vocal cords or vocal folds which in turn produces a voice frequency that is used for the transmission of speech.
During the absence of an input signal, the state of the 12 V relay RL1 is at OFF condition as regulated by the 10K Ohms trimmer RV1. The circuit can be made to react with its sensitivity in points A, B, & C, where a negative feedback can be placed due to the addition of band pass filter. The filter will operate only in the 1 KHz range and the circuit will only correspond at this frequency.
During the absence of an input signal, the state of the 12 V relay RL1 is at OFF condition as regulated by the 10K Ohms trimmer RV1. The circuit can be made to react with its sensitivity in points A, B, & C, where a negative feedback can be placed due to the addition of band pass filter. The filter will operate only in the 1 KHz range and the circuit will only correspond at this frequency.
The signal and tone activated relay switch were used in a wide range of fields which includes measuring instruments, audio systems, communications equipment, and factory-automation equipment. They can also be found on telephone subscriber circuits for the polarity reversing switch, testing, and ringing functions. Source
Monday, November 18, 2013
Solid State Relay Required Only 50uA Drive Current
This circuit demands a control current that is 100 times smaller than that needed by a typical optically isolated solid state relays. It is ideal for battery-powered systems. Using a combination of a high current TRIAC and a very sensitive low current SCR, the circuit can control about 600 watts of power to load while providing full isolation and transient protection.
Solid State Relay Circuit diagram:
Solid State Relay Circuit diagram:
Source: Discover Circuits
Saturday, November 16, 2013
Relay Control with MOSFET IRF511
We would like ti show you the circuit is similar to the above, but uses an N-channel MOSFET, as IRF511, 540, 640, etc. instead of the NPN transistor. Smaller MOSFETs can be used, but I do not know the part numbers. I tested the circuit with a IRF640, IRF511, IRFZ34 and REP50N06. The same circuit has three advantages, but requires only a few parts, always off to the relay and do not need a switch debounce.
In operation, when the relay is deactivated, the 100uF capacitor charge up to 6 volts. When the button is pressed, is on the capacitor 6 volts at the gate MOSFET. The capacitor voltage (and gate voltage) of 6 ms should drop to 3 volts in about 200 to move enough time for relay contacts. At very slow relay, a larger capacity. With the ratification of the relay, the contacts 12 volts to the resistance produce valid 3.3K 6 volts at the gate, holding that the relay is self-sufficient. The capacitor is then discharged to zero since the relay contact 12 is connected not to the 15K resistor.
Relay Control with MOSFET IRF511 Circuit Schematic
When the button is pressed, the capacitor is zero volts to the gate of switching off the relay. There should be no problem making the button again to be the operation of relays, since the gate voltage is only about 1.8 volts when the button is pressed and the MOSFET requires approximately 3.5 volts or more are to start running. But you wait about 1 second or more between pressing a key need, capacitor time to load or unload. Two buttons are displayed, but you could have a number of more parallel to operate the relay from multiple locations
In operation, when the relay is deactivated, the 100uF capacitor charge up to 6 volts. When the button is pressed, is on the capacitor 6 volts at the gate MOSFET. The capacitor voltage (and gate voltage) of 6 ms should drop to 3 volts in about 200 to move enough time for relay contacts. At very slow relay, a larger capacity. With the ratification of the relay, the contacts 12 volts to the resistance produce valid 3.3K 6 volts at the gate, holding that the relay is self-sufficient. The capacitor is then discharged to zero since the relay contact 12 is connected not to the 15K resistor.
Relay Control with MOSFET IRF511 Circuit Schematic
When the button is pressed, the capacitor is zero volts to the gate of switching off the relay. There should be no problem making the button again to be the operation of relays, since the gate voltage is only about 1.8 volts when the button is pressed and the MOSFET requires approximately 3.5 volts or more are to start running. But you wait about 1 second or more between pressing a key need, capacitor time to load or unload. Two buttons are displayed, but you could have a number of more parallel to operate the relay from multiple locations
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