Solid State Relays Circuit

Welcome to Free circuit dot com ,today we have classic circuit to implement solid state relay in your electronic project .

Solid state relays are almost everywhere these days, but they are very expensive. So, your efforts to build their own salary. Especially since it’s only a few parts and circuit simple and straightforward. Solid state relay is not really at all relays. There are no “relay” is available only with electronics, connection works. It works well as a relay, you can use low voltage higher and better. “Relay” between 115/220V AC wires in place, although it was customary, the neutral conductor and leave unchanged phases and neutral.

As long as no voltage (left in picture), the phototransistor TIL111 blocks of energy, and thus is not available. To ensure that the base TIL111 is fed to the transmitter (s) through the 1M resistor. This method prevents the base of transistor BC547B will be low and remains biased ‘on’. Collector is low and the gate (g) TIC106M thyristor, which is still in the country, “off”. 4-diode bridge rectifier circuit has no power apart from a small base and collector current BC547B, which is not enough to turn over the 330-ohm resistor TIC226M triac. Current “Load”, is very small.

With an input voltage, say 5 volts, the diode in the TIL111 lights up and activates the phototransistor. The voltage drop 1MEG ohm resistor in series with 22K resistance increases demand, which block the BC547B transistor. Collector current of the fact that the AC voltage falls below a certain value, which is VA. This ensures a sufficiently large voltage drop across the resistor 330 ohms triac switches ‘on’. The voltage on triac is currently only a few volts, so that practically the whole 115/220 AC voltage on the “Upload”.

The triac is a 100nF capacitor and impedance of 47 ohms, 100nF capacitor for the 330 ohm resistor is to protect the triac to be undesirable distortions caused by small peaks. To create the possibility of this circuit with different voltages to be switched, added BF256A FET. The FET acts as a current source from the source (s) with a gate (g). This means that this FET determines the current TIL111, regardless of the input voltage (up to a certain tolerance, of course). 1N4148 diode is to protect the circuit from reverse polarity.
(Tony: TIL111 is a so-called “optical coupling” with NPN output and can be replaced with NTE3042)

Good point line, as is the separation of AC and DC voltage, so this circuit is used in many applications, about 1.5 kW, when the triac is mounted on the large size of the cooling fins.
“M” appears Triac means it’s 600volt type, “D” for 400V. So be sure to go to the M-type.

NTE replacement for this circuit are 600volt types which are more than sufficient for our 110/115VAC. Even if you decide to print for this circuit is enough space between the lines AC and non AC these tracks to be close.

VU 220V Circuit

Welcome back to free circuit dot com, What has circuit today ?

For those who like the sound and light system. Today I get to see the VU lamp 220V circuit.
We may see a small LED in the circuit, but we put a sign of coming out with VU and Opto MOC3021M Triac combined to drive the lamp to light.
This circuit is used OptoCoupler Number MOC3021M NL =11 Pcs.
Triac uses a number BT139-600E 11 + signature print and a electronic device.
The stability and make the budget more than $ 15.

For all electronic device list ,you can look at the number on the PCB and part assembly.

you can bring signal from UV IC or LED signal to connect with Opto

Thus as below show device assembly layout.

VU 220 Lamp Device Lay Out

Photo sensor control relay circuit

Welcome back to Free circuit dot com,a good day, We have new circuit for control relay with photo sensor .

A photo or slightly activated relay normally open relay in the closed circuit / contact with the light. In this circuit, a photodiode is used to sense light. The photodiode has a high resistance in the absence of light strikes. The photodiode is connected to the reverse biased state. The only current flowing through it will be due to minority carriers.
When light falls on it, the minority current carriers in the wake of increasing the diode provides a low resistance. Because the voltage across the diode will not be sufficient to bias transistor Q1 and will be reset. Where there is darkness, the resistance increases photodiode and the voltage across it will be enough to move forward bias the transistor Q1 of the relay ON. The diode D2 is used as a diode to protect transistor switching transients produced relay. In this way, the load on the relay contacts can be switched on and off using light strikes the photodiode.

relay control mosfet circuit

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.

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

automatic turn off relay circuit

Per request the circuit today we have relay circuit.

It is worth noting again that the diagram provides a time delay of about 0.5 seconds for every microfarad in the value of capacitor C1.

This permits delays of up to several minutes. If desired, the delay periods can be made variable by replacing resistor R2 with a fixed and variable resistor in series whose nominal values are approximately equal of the total value of R2 (680K).

flip-flop circuit

Today , i would like to present for basic flip-flop which circuit is an example of a set / reset flip-flop using discrete components. When power is applied, only one of the transistors, which would allow the other to stay outside. The conductive transistor can by grounding the base by the push by the collector voltage to rise and set off across the transistor causes.

Light activated circuit

Today,We have two simple circuit is a transistor switch to the base of the transistor with a voltage divider. The voltage divider consists of two resistors. The first is the 100K Potentiometer 1K plus protective layer resistance. Secondly, the resistance of LDR. This is the schematic representation of the circuit:

When the light changes on the surface of the LDR, LDR is the resistance. The more light, the lower the resistance of the LDR, the less friction, the lower the voltage over it. The less light, the greater the resistance and thus the greater the voltage across it.

Part List

D1 = 1N914
Q1=2N2222 OR similar NPN transistor
R1 =Photoresistor
R2=50K Variable Resistor
R3=1K
Relay = 5 to 6 volt relay.

When the voltage increases, the SD of the 2N2222 transistor and thus the ICE increases accordingly, until the current is sufficient to activate the relay.

The amount of light that can be changed to activate the relay by a change in the 100k potentiometer. In short, any change in the potentiometer to the voltage loss of the LDR effects because they are both members of the voltage divider are described above.

The 1N4001 diode is used to eliminate stress again, if the relay is turned off. It is very important to the diode, as can be damaged without the transistor.
Before serving work as far as the activation. It will not detect a problem, dark or light or operate the relay, but it will be a problem if the relays are released. At this point, the circuit has a large hysteresis. Therefore, we must continue to strengthen the signal before we apply to the switching transistor.

We will BC517 NPN Darlington transistor pair. Should we 2N2222 between him and the LDR, as the following circuit shows:   

Dark activated circuit

This addition increases the sensitivity of the circuit. The hysteresis window is decreased significantly, but there is still an area known as the relay is activated, it will not be rotated by the same amount of light that existed just prior to activation.
Only an adjustment and that would (of course) potentiometer. Your goal is to operate the circuit when the relay is equal to or less light to the predefined value. The easiest way to do this is as follows:

Let the LDR by the amount of light illuminates you. Hold the potentiometer in the highest value. Then start slowly turning the potentiometer and reduce drag. If you “click” of the relay listen to find your reference. From that moment every time the light is less than or equal to (or more if the circuit is turned on the light “as configured) is to light that you have created this preference is enabled the relay.

DEW sensor circuit

Dew (condensed moisture) ad- versely affects the normal per- formance of sensitive electronic devices.A low-cost circuit described here can be used to switch off any gadget automatically in case of excessive humidity.At the heart of the circuit is an inexpensive (resistor type) dew sensor element.

Although dew sensor elements are widely used in video cassette players and recorders, these may not be easily available in local market. However, the same can be procured from authorised service centres of reputed companies. The author used the dew sensor for FUNAI VCP model No. V.I.P. 3000A (Part No: 6808-08-04, reference no. 336) in his prototype. In practice, it is observed that all dew sensors available for video application possess the same electrical characteristics irrespective of their physical shape/size, and hence are interchangeable and can be used in this project. The circuit is basically a switching type circuit made with the help of a popular dual op-amp IC LM358N which is configured here as a comparator.

(Note that only one half of the IC is used here.) Under normal conditions, resistance of the dew sensor is low (1 kilo-ohm or so) and thus the voltage at its non-inverting terminal (pin 3) is low compared to that at its inverting input (pin 2) terminal. The corresponding output of the comparator (at pin 1) is accordingly low and thus nothing happens in the circuit.

When humidity exceeds 80 per cent, the sensor resistance increases rapidly. As a result, the non-inverting pin becomes more positive than the inverting pin. This pushes up the output of IC1 to a high level. As a consequence, the LED inside the opto-coupler is energised.

At the same time LED1 provides a visual indication. The opto-coupler can be suitably interfaced to any electronic device for switching purpose. Circuit comprising diode D2, resistors R5 and R6 and capacitor C1 forms a low-voltage, low-current power supply unit. This simple arrangement obviates the requirement for a bulky and expensive step-down transformer.

Water Activated Relay circuit

For electronic circuit has two transistors wired as a pair, together with high gain.