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diy k152 |
Countdown Timer w/Relay
Output
Countdown Timer kits are an ever popular item with the hobbyist. One of the main methods used is the ever-popular 555 timer IC.
In this countdown timer circuit we use a 555, a counter IC and a transistor switch to activate a relay either on-to-off or off-to-on
(mode selected by a jumper) as soon as the counting period is over. The circuit consists of 3 parts: an oscillator, a ripple counter
and two switching transistors.
Specifications:
- L: 2" W: 2-1/4" H: 5/8"
- Requires external
12 volt dc power supply
(Need a Power Supply?)
- Jumper Selectable count down times ( 8 to
8192 seconds)
- Relay has Normally Open and Normally Closed Contacts
rated for voltages 28VDC @ 10A, 125VAC @ 10A, or 240VAC @ 7A.
(more
info on how relays work)
See
CK1611.pdf for complete
details, including schematic and theory of operation. Requires
Adobe Acrobat Reader available at
www.adobe.com
for FREE!
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