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Miscellaneous: Timers: Countdown Timer Schematics and Circuits

Count-Down Timers

Photo: Universal Relay Timer-Switch Electronic Kit Universal Relay Timer-Switch Electronic Kit
Set this relay-based timer for anywhere from a few seconds to about 15 minutes so that you can time on/off almost anything.
Photo: Multi Mode Timer Circuit Multi Mode Timer Circuit
This timer kit contains seven different timing modes using only ONE IC and some support components on a single-sided PCB.
Photo: Count-Down Timer - Relay Output Switch Count-Down Timer - Relay Output Switch
Timer kits are an ever popular item with the hobbyist. This uses a 555 timer IC and goes from 8 seconds to 8192 seconds.
Photo: Timer Circuits Relay Switches Timer Circuits Relay Switches
Timer circuits are handy for many experimenters projects, not to mention the photo lab. This kit has three separate circuits that can be used individually or together. Each circuit has a separate 5 Amp relay. Circuits operate on 9 Volt DC.
An electronic circuit that uses a 556 (Dual timer) IC to produce a two-tone train horn sound effect. Equivalent circuit using two 555 timers (single timers) is given.