Motorcycle temperature Gauge

2009-03-16T23:12:00.002-07:00

This project is a circuit for measuring the heat of a motorcycle engine. This circuit is very easy to build. Just use a LM3914 IC and ten LEDs as indicators. You can use the thermistor is worth 47K or 10K. What is important is the adjustment of the VR to adjust the sensitivity level required.

DC-DC Converter

2009-03-16T23:12:00.001-07:00

5V regulator on 45v

2008-12-31T09:18:00.000-08:00

The type 7805 voltage regulator cannot handle input voltages higher than 35v. If only voltages higher than 35v are available, it is, of course, posible to shunt the input with a zener diode. However, since prices of standart voltage regulators are low, there are advantages in using a second regulator: the stability of the output voltage as well as the hum rejection will be improved appreciably.
In the present circuit, the 7805 is preceded by a 7824. To obtain as high an input voltage rating as posible, the centre pin of the 7824 is not connected to ground, as is usual, but to the out put of the 7805. The maximum input voltage must satisfy the rule that each of the Ics must have a difference between its input and output of not less than 3 v. The output of IC1 is 24+5=29 v, which is more than enough for IC2. Since IC1 must also obey the rule, its input must be 3 v higher than its output, that is 29+3=32 v.

Owing to the large difference in input voltage and output voltage, the maximum output current is somewhat restricted. The 7805 has a voltage of 24v across it, so that it dissipated 2 w when the output current is 80mA. Without a heatsink, the trigger point of the thermal protection of this IC would then have been reached. This means that the IC must be fitted on an ample heatsink.

Electronic Circuit Projects

Motorcycle temperature Gauge

DC-DC Converter

5V regulator on 45v