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A Tan Timer Circuit (BC337 )

2017-08-04 21:55  
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This article briefly describes the A Tan Timer Circuit (BC337). This principle is easy to understand, but also very practical. Depth understanding of circuit elements, you can better grasp this principle. In this circuit, you can learn about and purchase these components: BC337.

Six timing positions suited to different skin types, Timing affected by sunlight intensity

This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight. A Rotary Switch sets the timer according to six classified Photo-types (see table). A Photo resistor extends the preset time value according to sunlight brightness (see table). When preset time ends, the beeper emits an intermittent signal and, to stop it, a complete switch-off of the circuit via SW2 is necessary.

Circuit diagram:

Figure:1 Tan Timer Circuit Diagram

Figure 1 Tan Timer Circuit Diagram


R1 = 47K – 1/4W Resistor
R2 = 1M – 1/4W Resistor
R3 = 120K – 1/4W Resistors
R4 = Photo resistor (any type)
R5 = 120K – 1/4W Resistors
C1 = 10μF – 25V Electrolytic Capacitors
C2 = 220nF – 63V Polyester Capacitor
C3 = 10μF – 25V Electrolytic Capacitors
D1 = 1N4148 – 75V 150mA Diodes
D2 = 1N4148 – 75V 150mA Diodes
Q1 = BC337 – 45V 800mANPNTransistor
B1 = 3V Battery (two 1.5V AA orAAAcells in series)

IC1 = 4060 – 14 stage ripple counter and oscillator IC
IC2 = 4017 – Decade counter with 10 decoded outputs IC
SW1 = 2 poles 6 ways Rotary Switch (see notes)
SW2 =SPSTSlider Switch
BZ1 = Piezo sounder (incorporating 3KHz oscillator)


Figure 2 

Needing only one time set suitable for your own skin type, the rotary switch can be replaced by hard-wired links.
ADIP-Switch can be used in place of the rotary type. Please pay attention to use only one switch at a time when the device is off, or the ICs could be damaged.



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