120 and 240Vac LED Voltage Indicator Circuit

Useful for power lines control Simple, transformerless circuitry

This circuit, designed on request, has proven to be useful to indicate when the voltage in a power supply line is changing from 120V to 240Vac. It can be used in different circumstances and circuits, mainly when an increase in ac or dc supply voltage needs to be detected. D3 illuminates when the line voltage is approaching 120V and will remain in the on state also at 240V supply. On the other hand, D6 will illuminate only when the line voltage is about 240V and will stay on because the latching action of Q1, Q2 and related components. C1, D1 and D2 provide a low dc voltage in the 4.5V - 6V range in order to allow proper operation of latch circuit and LEDs.

Circuit diagram :

 120 and 240Vac LED Voltage Indicator Circuit diagram

Parts :

R1_____________470R  1/2W Resistor
R2_____________220K  1/4W Resistor
R3,R7__________470R  1/4W Resistors
R4_______________1K  1/4W Resistor
R5_______________2K2 1/4W Resistor
R6_____________330R  1/4W Resistor

C1_____________330nF 630V Polyester Capacitor
C2______________10µF  25V Electrolytic Capacitor

D1,D2________1N4007   1000V  1A Diode
D3,D6___________LEDs  (Color and shape at will)
D4_________BZX79C10   10V 500mW Zener Diode (See Notes)
D5___________1N4148   75V 150mA Diode

Q1____________BC547   45V 100mA NPN Transistor
Q2____________BC557   45V 100mA PNP Transistor

Notes:

• D4 value could require some adjustment in order to allow precise switching of the circuit at the chosen voltage. If the case, please try values in the 8.2V - 15V range.
  
• Warning! The circuit is connected to 240Vac mains, then some parts in the circuit board are subjected to lethal potential! Avoid touching the circuit when plugged and enclose it in a plastic box.

Source : www.redcircuits.com

Water Pump Relay Controller Circuit Schematic

Water reservoir automated stage keep watch over, Simple circuitry - 12V supply

By manner of a Relay, employed to power a water pump, this circuit gives automated degree keep a watch on of a water reservoir or well. The shorter metal rod is the "water high" sensor, whereas the longer is the "water low" sensor. When the water degree is beneath each sensors, IC1C output (pin #10) is low; if the water grow to bes in touch with the longer sensor the output is still low until the shorter sensor is reached. At this point IC1C output goes excessive, Q1 habitss, the Relay is energized and the pump starts running.

Now, the water stage commences to lower and the shorter sensor will be not in touch with the water, but IC1C output will most definitely be cling high through the signal return to pin #5 of IC1B, so the pump will continue its operation. But when the water stage falls beneath the longer sensor, IC1C output goes low and the pump will cease. SW1 is not obligatory and used to be delivered to offer reverse operation. Switching SW1 to be ready to join R3 to pin #11 of IC1D, the pump will operate when the reservoir is kind of empty and will stop when the reservoir is full. In this case, the pump will likely be used to fill the reservoir and to not empty it as within the default running mode.

Circuit diagram:

 Water Pump Relay Control Circuit Diagram

Parts:
R1 = 15K - 1/4W Resistors
R2 = 15K - 1/4W Resistors
R3 = 10K - 1/4W Resistor
R4 = 1K - 1/4W Resistor
D1 = LED - any kind and colour
D2 = 1N4148 - 75V 150mA Diode
Q1 = BC337 - 45V 800mA NPN Transistor
IC1 = 4001 Quad 2 Input NOR Gate CMos IC
SW = SPDT Toggle or Slide Switch (Optional)
RL1 = Relay with SPDT 2A @ 230V change
Coil Voltage 12V - Coil resistance 200-300 Ohm
Two steel rods of acceptable length

Notes:

• The two metal rods should be supported by a small insulated (wooden or plastic) board.
• The circuit can be used also with non-metal tanks, provided a 3rd metal rod having about the identical height of the tank will doubtless be introduced and linked to the circuits poor floor.
  

 

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