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3-way switch diagram (power ... 3-way-switch-diagram (light ... ... Wire a Basic 3-Way Switch: 3 way switch wiring diagram 3-Way Switch Diagram (Multiple ... 3 way switch wiring diagram This wire should be marked ... Hey, doing it yourself is ...

Pumping of water into a tank is accomplished by motor operation. When the tank is about to be full with water, the motor pump is about to stops to operate. When the tank is about to be emptied, the motor pump will start to operate. Float Switch Motor Pump Control Operation Figure below (A) shows a tank half filled with water. The motor pump M at idle condition. Water flows out from the gate valve L. Lever C is tilted downward to the right because of the weight W1. Mercury B is at the right position inside the glass container A. the metal rods X and Y inside the sealed glass container A are at open condition. Float bulb K float over the water J inside the tank. Float bulb K goes down as the water drops down. (A) Water is withdrawn from the tank. Water level drops downward. When the water level drops down beyond the stopper E, Figure below (B) the stopper E prevents float bulb K to go down further. When the water level goes down further weight W2 the effect of the combined weight of flo...

This inexpensive, fully transistorised switch is very sensitive to sound signals and turns on a lamp when you clap within 1.5 metres of the switch. One of its interesting applications is in discotheques, where lights could be turned on or off in sync with the music beats or clapping. Sound-Operated Switch for Lamps Circuit Diagram The condenser microphone senses the sound and converts it into electrical variations. The electrical signals are amplified by the two-stage direct-coupled (DC) amplifier formed by transistors T1 and T2 and fed to the switching circuit. The switching circuit comprises transistors T3, T4 and T5, which conduct only when the circuit senses sound signals. Transistor T5 supplies sufficient gate voltage to the triac to drive the 230V lamp. The regulated 12V DC power supply for the circuit is derived from AC mains by using resistor R14, diode D1 and zener diode ZD1. The circuit can be assembled on any general-purpose PCB. Soursed By: EFY: Author Pradeep G.

Simple 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. Circuit diagram: Automatic 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 lo...

Here is another simple circuit to mute the volume of Audio devices through simple touch. It exploits the action of the flip-flops in the timer IC 555 to reduce the volume of the Audio amplifier. IC NE555 is designed in the toggle mode. Its lower and upper comparator inputs are connected to the touch plates which can be membrane switches or two pieces of conducting plates. The inputs of comparators are stabilized through R1 and R2 to avoid floating. Touch controlled Mute switch circuit diagram   When the touch plate connected to pin 2 is touched momentarily, output of IC1 goes high and T1 conducts. The centre tap of the volume control is connected to the collector of T1. So when T1 conducts current going to the amplifier drains through T1. This reduces the volume.IC1 remains latched in this position with LED on. When the touch plate connected to pin 6 is touched momentarily, output of IC1 goes low and T1 turns off. This restores the volume.

This is a very simple electronic circuit project of light sensitive and differential temperature switch circuit.   In Fig. 1 see a precision light- sensitive switch that activates when the sensed quantities go above or below pre-set values. The LDR can be any cadmium – sulfide unit that has a resistance in the range 500R to 20k at the required trip level. The RV1 adjust LDR at normal light level. In Fig. 2 see a differential temperature switch circuit using ordinary silicon diodes as temperature – sensing elements and responding to differentials of a fraction of degree. RV2 can be used to apply an effective offset of several degrees to the two diodes. To adjust the circuit, apply the required differential temperature to the diodes and then adjust RV2 so that the relay just turns on. The circuit responds to the relative temperatures, rather than the absolute temperatures, of the two diodes.

We  can make a simple touch switch using only two inverter gates, two resistors, and two capacitors. The schematic diagram of the circuit is shown in the figure below. At power up, the output (of U1A) will be high, and the inverting output will be low because U1A gate will be triggered to ground level by C2. After triggered, the low level of U1A input is maintained by U1B output via R2. Toggle Touch Switch Using Two Inverter Gates Circuit Diagram If we touch the pad at this condition, where the output is high, then the U1A input will go high because we “short” the voltage of C1 to the input pin, and the low level previously caused by low level of U1B output voltage connected via R2 can’t be maintained because our skin resistance is much lower than 10M. After U1A input goes high then U1A output will go low, and now U1B will go high to maintain high voltage level of U1A via R2, so we can release our finger without loosing the last state. Touching the pad again after we release our pr...

This simple ON OFF touch switch circuit is based on the well known timer IC 555 (IC1), which drives a relay that acts like a switch. The metal surfaces can have what form we want, but it should be clean and very close to the circuit. Read more  WC fan using 555 Touch plate MP1 in order to close the contact of relay RL1 [ON], or plate MP2 in order to open the contact of RL1 [OFF]. The Led D2 turns on when the contacts of RL1 are closed. Two small pieces of metal can be used as sensor plates. 555 ON/OFF Touch Switch Schematic     Parts List R1 = R2 = 3.3M R3 = 10K R4 = 1K C1 = 10nF D1 = 1N4007 Q1 = BC547 IC = NE555 12V relay Sourced By: Circuitsstream

This AC mains-operated bistable  switch turns on or turns off a  device using a miniature neon  lamp and a few discrete components.  This switch can be used for control pan-els, appliances and lighting controls.  A push-to-on switch is used to  light up the neon lamp. The light emit-ted by the neon lamp, in turn, enables  the switching action of the circuit. Use  of a 555 timer wired for bistable operation makes the circuit act as a bistable  switch. Circuit diagram : AC Mains Bistable Switch Circuit Diagram   The neon lamp (NL1) and the  push-to-on switch (S1) are directly connected to 230V AC mains. The 12V DC  supply for timer 555 (IC1) is derived  from 230V AC mains through capacitive dropper C1, resistor R1 and a 12V  zener diode. IC1 works as a flip-flop  circuit, with the signal at its output  pin 3 toggling every time it receives a  pulse at its pins 2 and 6.  The operation of the circuit ...

This cell-phone-controlled audio/video mute switch is highly useful in automobiles. The circuit automatically disconnects power supply to the audio/video system whenever the mobile handset is lifted off the holder for making or receiving a call. You can use any readily available cell-phone holder with some minor alterations or fabricate it yourself as shown in Fig. 1. Fig. 1: Proposed cell-phone holder The circuit is wired around IC LM555 (IC1), the CMOS version of timer NE555, as shown in Fig. 2. IC1 is used as a medium-current line driver with either an inverting or non-inverting output. It can sink (or source) current of up to 50 mA only, so take care while handling it. The audio/video system is connected to the circuit via normally opened (N/O) contacts of the relay. Fig. 2: The circuit of the cell phone-controlled audio/video mute switch When the cell phone is in its holder, LDR1 does not receive any light from white LED1 and its resistance is high. As a result, the voltage at pi...

Here is very simple and easy build a sound operated switch electronic circuit project. A sound operated switch with a relay driver. Simple Sound Operated Switch Circuit Diagram: Notes: This sensitive sound operated switch can be used with a dynamic microphone insert as above, or be used with an electret (ECM) microphone. If an ECM is used then R1 (shown dotted) will need to be included. A suitable value would be between 2.2k and 10kohms. The two BC109C transistors form an audio preamp, the gain of which is controlled by the 10k preset. The output is further amplified by a BC182B transistor. To prevent instability the preamp is decoupled with a 100u capacitor and 1k resistor. The audio voltage at the collector of the BC182B is rectified by the two 1N4148 diodes and 4.7u capacitor. This dc voltage will directly drive the BC212B transistor and operate the relay and LED. It should be noted that this circuit does not "latch". The relay and LED operate momentarily in response to a...

Simple 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. Circuit diagram: Automatic 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 lo...

One of the common  rounds in the  quizzes is the buzzer round. We are describing here a simple electronic circuit that can be used in any test or quiz competition. In this circuit, only four persons can participate,  and  every  participant is assigned a certain number. Whenever a switch is pressed, the circuit locks the remaining three entries. At the same time, an alarm sounds and the designated switch number is displayed on the seven segment LED display.When a player presses his switch, the corresponding output of IC1 goes high. Let us suppose, when switch S1 is pressed, D1 input of IC1 goes low and its corresponding output Q1 goes high. As a result, current passes through D5 to piezo buzzer PZ1, which creates a beep. At the same time, current also passes through diodes D6-D7 to show the number on the LED display. Simple Electronic Quiz Switch Circuit Diagram Simple Electronic Quiz Switch Circuit Diagram Similarly, when any other switch (S2-S4) is pressed, t...

The SMPS described here is suit-able for high-wattage stereos and other similar equipment. The circuit employs two high-voltage power transistors (BU208D) which have built-in re-verse-connected di-odes across their collectors and emitters. It can supply about 250-watt out-put. The circuit uses a ferrite core transformer of 14mm width, 20mm height, and 42mm length of E-E cores. An air gap of 0.5 mm is required between E-E junction. Good insulation using plastic-insulating sheets (Mylar) is to be maintained between each layer of winding.  Switch Mode Power Supply Circuit Diagram The number of primary turns required is 90 with 26 SWG wire. The secondary winding employs 17 SWG wire (for 4A load current). Each turn of the secondary develops approximately 2 volts. The reader can decide about the output volt-age and the corresponding secondary turns, which would work out to be half the desired secondary voltage. The volt-age rating of capacitors C7 and C8 should be at least twice the seco...

This electronic timer switch project is a good project to build to simulate the presence of occupants in a house. In these days when security is becoming more of a concern when no one is at home, having this device will deter the thief from breaking in. Circuit Diagram    The core of this electronic timer switch project uses a CD4060B binary counter. The binary counter has 10 outputs and the counter are counted by configuring the oscillator. Every negative clock will trigger the counter of the IC internally.The timing of the circuit is affected by resistor R3(1M ohm) and capacitor C2(0.1uF). By connecting the four outputs in an AND configuration, the transistor Q1 will only turn ON if all the 4 outputs are in logic "1". If any of the logic is "0", the transistor will remain OFF. For a complete cycle, the transistor will be ON twice when the output at pin 15, QJ goes to logic "1" and "0" twice when the other outputs QL, QM and QN remain at "1...

Control by sound may be very useful,  not just on a robot but also for a bit  of home automation, for example a  sound activated light responding to a  knock on the door or a hand clap. The  light will be automatically switched  off after a few seconds. An alternative  use is burglar protection — if someone  wants to open the door or break some-thing the light will come on, suggesting  that someone’s at home. The circuit can work from any 5– 12 VDC regulated power supply pro-vided a relay with the suitable coil voltage is used.   Circuit diagram :   Sound Activated Switch Circuit Diagram When you first connect the supply  voltage to the circuit, the relay will  be energised because of the effect of capacitor C2. Allow a few seconds for  the relay to be switched off. You can  increase or decrease the ‘on’ period  by changing the value of C2. A higher  value results in a longer ‘on’ period,  and vi...

Electrical appliances accidentally left on  in (holiday) homes left unoccupied for a  short or a long period consume power  unnecessarily and can present a fire hazard. Everyone will be familiar with those  nagging thoughts, a few miles down the  road from the house: “Did I remember  to switch off the coffee machine? The  lights? The oven?”  Automatic AC Power Switch Circuit Diagram Hotel rooms are often equipped with a  switch near the main door which enables the power supply to everything in  the room only when the plastic card (which  might contain a chip or have a magnetic strip  or a pattern of holes) that serves as the room  key is inserted. The circuit idea given here  to switch off lights and other appliances is  along the same lines. The solution is surprisingly simple.  A reed contact is fitted to the frame of the main entrance door, and a matching magnet  is attached to the door itself such t...