Here is a Simple Electronic Circuit Project of Simple Pushbutton Switch This circuit acts like a two-position switch but is operated using a pushbutton. After power has been applied, the circuit is in the following initial state: the bases of T1 and T2 are at the positive supply potential and the base of T3 is at ground potential. All transistors are cut off. The other contact of the pushbutton is at ground potential. No current flows through the relay coil and the status LED is off. Pushbutton Switch Circuit Diagram: If the pushbutton is pressed, T2 and (after a slight delay due the RC network) T3 switch on. The collector of T3 is now nearly at ground potential, so current flows through the relay coil and the function LED is illuminated. T1 can also switch on. This situation is stable, since ground potential can reach the base of T2 via R1, so nothing changes when the pushbutton is released. C1 is charged via R3 to cause a positive potential to be present at the pushbutton. I...
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Description It sounds rather mysterious: a switch that is controlled by its ambient temperature. All without the touch of a human hand, except for when you’re building this sort of electronic thermostat. There are a lot of handy uses for a thermally controlled switch. If the temperature inside your PC gets too high sometimes, the circuit can switch on an extra fan. You can also use to switch on an electric heater automatically if the room temperature is too low. There are innumerable potential applications for the thermostat described here. Circuit diagram: There are lots of ways to measure the temperature of an object. One very simple way is to use a semiconductor sensor, such as the National Semiconductor LM35 IC. This sensor is accurate to within 0.5 °C at 25 ºC, and few other sensors can do better or even come close to this level of accuracy. In the circuit described here, the sensor (IC2) generates an output voltage of 10 mV/°C, so the minimum temperature that can be measured is 0...
Description The modern mechanic switches are improved concerning of old technology. We need however many times to replacement some old switch or to check currents bigger than the durability of certain switches or simple we need something with modern appearance. For he and different reasons is essential the up circuit. It is simple in the manufacture and the materials that use they exist everywhere. Circuit Diagram: Parts: R1 = 3.3M R2 = 3.3M R3 = 10K R4 = 1K C1 = 10nF-63V D1 = 1N4007 D2 = Red LED Q1 = BC547 IC1 = NE555 RL1 = 12V Relay Circuit Operation: This circuit is based on the well known timer IC 555 (IC1), which drives a relay of which the contacts play the role of switch. The metal surfaces can have what form we want, but it should they are clean and near in the circuit. In order to it changes situation it suffices touch soft somebody from the two plates. Plate MP1 in order to the contacts of RL1 close [ON], or plate MP2 in order to the contacts of RL1 o...
Theory of operation remain the same so please take a look at the previous Article about MAINS Power Switch for deeper explanations. I don’t know if this it’s the smallest MAINS Power Switch with integrated WIFI and direct Web interface access but if is not, it’s definitely closer to be at only around 25x50mm :) [ ]
A 4-Digit Keypad Controller Switch Circuit This is a universal version of the Four-Digit Alarm Keypad . I have modified the design to free up the relay contacts. This allows the circuit to operate as a general-purpose switch. It also means that it can be used to control all of my Alarm Circuits. I've used a SPCO/SPDT relay - but you can use a multi-pole relay if you wish. The relay is energized by pressing a single key. Choose the key you want to use - and connect it to terminal "E". Choose the four keys you want to use to de-energize the relay - and connect them to "A B C & D". Wire the common to R1 and all the remaining keys to "F". The Circuit is easy to use. When you press "E" - current through D2 & R9 turns Q6 on - and energizes the relay. The two transistors - Q5 & Q6 - form a "Complementary Latch". So - when you release the key - the relay will remain energized. To de-energize the relay - you need to press keys ...
Automatic Switch For Audio Power Amplifier. Circuit of an automatic switch for audio power amplifier stage is presented here. The circuit uses stereo preamplifier output to detect the presence of audio to switch the audio power amplifier on only when audio is present. The circuit thus helps curtail power wastage. IC1 is used as an inverting adder. The input signals from left and right channels are combined to form a common signal for IC2, which is used as an open loop comparator. IC3 (NE556) is a dual timer. Its second section, i.e., IC3(b), is configured as monostable multivibrator. Output of IC3(b) is used to switch the power amplifier on or off through a Darlington pair formed by transistors T1 and T2. IC3(a) is used to trigger the monostable multivibrator whenever an input signal is sensed. Switch For Audio Power Amplifier Circuit Diagram: Under ‘no signal’ condition, pin 3 of IC2 is negative with respect to its pin 2. Hence the output of IC2 is low and as a result output of IC3(a)...
In recent years, the use of switch mode power supply (SMPS) has become more comon as more applications demand for greater power eficiency. It makes use of semiconductor (mostly MOSFET) fast switches to switch DC input that has been rectified at high frequency. The advantages of high frequency switching are that it reduces the size of inductor, capacitors & transformer used. Other advantages of switching power supply over linear power supply are : 1) High Efficiency (up to 90% and above for nice design). 2) Output can be higher than input. 3) Able to operate over a variety of input power supply. 4) Able to have over output. The setback of using SMPS compared to linear power supply is that it generates electrical noise which contributes to electromagnetic compatibility design issues & more part count. Buck Converter SMPS The SMPS circuit below from Power Integration makes use of LNK304 as its high frequency switch. Take note that this circuit is non isolated type which means tha...
This is a Simple Complementary metal–oxide–semiconductor connect switch circuit diagram , CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits. This connect switch does not rely on mains hum for switching-It-can be used with battery powered circuits. Simple Cmos Connect Switch Circuit Diagram Schmitt trigger IC1 forms a 100 kHz oscillator and IC2a which is biased into the linear region, amplifies the output and charges CI via the diode. IC2b acts as a level detector. When the sensor is touched, the oscillator signal is severely attenuated which causes CI to discharge and IC2b to change state.Sourced by : Circuitsstream
Audio Controlled Mains Switch Circuit diagram. It is often useful for audio or video equipment to be switched off automatically after there has been no input signal for a while. The function of the on-off switch in such equipment is then taken over by switch S2 in the accompanying diagram. It remains, however, possible to switch off manually by means of Si. Automatic switch-off occurs after there has been no input signal for about 2 minutes: this delay makes it possible for a new record or cassette to be placed in the relevant machine. The audio input to the proposed circuit may be taken from the output of the relevant TV set, amplifier, or whatever. The input earth is held at + 6 V with respect to the circuit earth by potential divider Ri-R2-R3-R4. The two 741s function as comparators: the output of ICi goes high when the in- put signal is greater than + 50 mV, whereas the out- put of IC2 goes high when the input signal becomes mor...
Dual High Side Switch Controller Circuit diagram : Dual High Side Switch Controller Circuit Diagram One of the most frequent uses of n-channel MOSFET’s is as a voltage controlled switch. To ensure that the MOSFET delivers the full supply voltage to the load it is necessary for the gate voltage to be a few volts above the supply voltage level. This can be a problem if no other suitable higher volt-age sources are available for use elsewhere in the circuit. The LTC 1982 dual high-side switch controller from Lin-ear Technology (www.linear-tech.com) solves this problem by incorporating a voltage tripler circuit in the gate driver stage. The gate voltage is limited to +7.5 V which is 2.0 V above the IC’s maximum operating voltage. It can directly drive the gate of logic-level MOSFET with a VGS(th) from 1.0 V to 2.0 V. A suitable n-channel logic level MOSFET would be the BSP 295. This device can switch up to 1.5 A and is available in an SOT 233 SMD package.
This is the Doorbell Warning Switch Circuit Diagram. This circuit will light a lamp at a remote location when the doorbell switch is pressed. his circuit should only be used with the solenoid type doorbells, the electronic type that play tunes will not work here. It is quite easy to miss the sound of a doorbell if you are watching TV , this circuit gets round the problem by providing a visual indication. As an alternative, a LED could also be used. You could just parallel a lamp across the doorbell, but this would mean extra drain from the doorbell batteries or transformer. Doorbell Warning Switch Circuit Diagram A series resistor, R1 is wired in series with the doorbell and reduces current flow, thereby increasing battery life. The value of R1 is chosen so that about 0.6 to 0.7 volts is developed across it, when the doorbell switch is pressed. I used a combination of a 22 ohm resistor in parallel with a 50 ohm. The voltage drop across R1 is sufficient to switch on the transistor,...
The above circuit is a light sensitive automatic switch which functions in the absence of light. We are using IC 4060 in this circuit which works as an oscillator and the generated signal is applied to the base of T4 transistor.Phototransistor T3 is in conduction by existence of light and it keeps the T5 transistor’s base at ground potential. When no light reaches the phototransistor, it gets in insulation. T3 reaches positive potential through 22kohm. T4 and T5 both gets in conductance. The oscillator signal reaches the optic coupler and lamp(s) shines.
The series of light switches this time slightly different from the voltage of work. The series of light switches can work directly on the AC power network. Light switches are using the main component of TRIAC and LDR. The circuit is very simple and the components were sold in the market. If you want a light reception sensitivity of this circuit can be arranged then the 3.3 MOhm resistor can be replaced with a variable resistor. For more details can be seen from the following series of images. Circuit Diagram With Triac Light Switch series is prisipkerjanya as dimers, but dimers control performed by the reception of light around the LDR. The lower the intensity cayaha received LDR then semkin bright lights. For installation LDR need to be considered so as not exposed to light from the lamp directly.