5 to 30 Minute Timer


Posted on May 15, 2012

A switched timer for intervals of 5 to 30 minutes incremented in 5 minute steps. Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I would strongly suggest a Tantalum Bead type.


5 to 30 Minute Timer
Click here to download the full size of the above Circuit.

Switch 3 adds an extra resistor in series to the timing chain with each rotation, the timing period us defined as :- Timing = 1.1 C1 x R1 Note that R1 has a value of 8.2M with S3 at position "a" and 49.2M at position "f". This




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Micro Power FM Broadcasting
Triangle-square wave oscillator
Simple continuity checker
Wien bridge oscillator circuit
Transform electromyographic signals into music
preamp HF VHF UHF SHF wideband MAR6
High PoE made easy
Home Automation Using GSM WithCircuit
Signal Conditioners Information
video sequencer using analog multiplexers
Fixing Laptops Motherboard
The use of low-power tube amp tube radios restructuring



Top