EngineeringSlash- The electronic projects,electronic project,electronic schematic,electronic design » 1.5 Volt Tracking Transmitter http://www.engineeringslash.com Engineering blog- electronic circuits , electronic projects,electronic schematic,electronic design,simple circuit and hobby circuits Tue, 09 Feb 2010 05:03:16 +0000 http://wordpress.org/?v=2.9.2 en hourly 1 1.5 Volt Tracking Transmitter http://www.engineeringslash.com/simple-circuits/1-5-volt-tracking-transmitter.html?nucrss=1 http://www.engineeringslash.com/simple-circuits/1-5-volt-tracking-transmitter.html#comments Sat, 23 Jan 2010 10:55:31 +0000 admin http://www.engineeringslash.com/?p=177

1.5 Volt Tracking Transmitter circuit

The current draw for this tracker is 3.7mA, so the 1.5V button cell will last awhile. What the heck am I suppose to hear you ask? When your circuit is working you should see the LED flash quite fast. Take your FM radio and search for the low-beat ‘humbe-humbe-humbe-etc’ equal to the flash of the LED (probably around the 100Mhz). Found it? If that position is interferering with a radio station you can fine-tune it with the variable capacitor. If you like to have the tracker around the 88Mhz you can do that by spreading the windings from the home-made coil just a bit (1/2 a millimeter or so). Anyways, play with it and learn. It is a nice project. The 12-inch antenna can be anything, it is not really that critical. I used a piece of 22 gauge flexible wire. I haven’t checked the range but will do that shortly.

* For stability, use a NPO types for C2 & C4.

* Resistance tolerance for R1 should be 1 or 2%.

* Frequency range is the usual 87-109Mhz on the FM dial.

* The coil is made from 22 ga ‘hookup’ wire, like the solid Bell phone wire. Leave the insulation on.

* The LED is the ‘High Brightness’ type for maximum illumination.

source electro-tech-online .com

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