need a cheapest timer with out transformer,minimal component - Electronic Circuits Projects Diagrams Free

ambrose · 26th November 2003, 02:28 PM

anybody out there with a timer circuit .

i am in search of a cheap timer to opperate a mosquito repelent device.a cyclic on off timer without transformer .the timing should be 15min -30 min mode .no micro controller stuff .if it is a cmos 4000 series good.

Russlk · 27th November 2003, 12:05 AM

The 4521BE is a 24 stage counter with oscillator, just add the necessary R and C. It won't drive a relay so you will need a transistor driver. The power required is low enuf that you can just rectify the 60 Hz and use a resistive divider to get 12 VDC.

Phasor · 27th November 2003, 07:41 AM

Have you considered going low-tech? - how about a mechanical timer?

ambrose · 27th November 2003, 08:42 AM

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26th November 2003, 02:28 PM	(permalink)
ambrose	need a cheapest timer with out transformer,minimal component anybody out there with a timer circuit . i am in search of a cheap timer to opperate a mosquito repelent device.a cyclic on off timer without transformer .the timing should be 15min -30 min mode .no micro controller stuff .if it is a cmos 4000 series good. __________________ life is not a problem to solve ,but an adventure to face

27th November 2003, 12:05 AM	(permalink)
Russlk	The 4521BE is a 24 stage counter with oscillator, just add the necessary R and C. It won't drive a relay so you will need a transistor driver. The power required is low enuf that you can just rectify the 60 Hz and use a resistive divider to get 12 VDC. __________________ see my website: www.geocities.com/russlk

27th November 2003, 07:41 AM	(permalink)
Phasor	Have you considered going low-tech? - how about a mechanical timer?

27th November 2003, 08:42 AM	(permalink)
ambrose	[b]thanks for ur reply[/b] :!: __________________ life is not a problem to solve ,but an adventure to face