Ultrasonic Range Meter

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Ultrasonic

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Light to Frequency Converter TSL220

A large area photodiode and current to frequency converter combined in a clear plastic 8-pin DIL package. The output is a pulse train whose frequency is directly proportional to the light intensity. The output is CMOS compatible (use a 3k3 pulldown resistor to drive LS TTL) and the frequency can be measured by pulse counting, period timing or integration techniques. The photodiode has a wide dynamic range, high sensitivity and high noise immunity. The output frequency range is determined by a capacitor in the range 10pf to 100pf, which permits the output frequency to fall within some suitable range for any given light intensity.

Intermittent wiper controller by 2N4401

The intermittent wiper circuit shown above causes the auto’s windshield wipers to wipe once every several seconds instead of constantly wiping. The circuit may be added to older cars to provide the intermittent function or it may be used to replace broken wiper circuits in modern cars. The delay is continuously adjustable with the potentiometer but switch selected fixed resistors may also be used, if desired. The circuit should be connected to +12 volts at the same point as the original wiper power switch so that the proper fuse protection is preserved. The 12 volt relay should have contacts rated for a few amps since the wiper motor will draw a considerable start current but most automotive relays are adequate. The circuit should be quite trouble-free and will work on the first try if no wiring errors are made!

PWM DC motor control with SG3525

This control circuit is ideal for the accurate control of DC motors as well as other applications like lighting levels and small heaters etc. The circuit converts a DC voltage into series of pulses, such that the pulse duration is directly proportion to the value of the DC voltage. The great advantage of such a circuit is that almost no power is lost in the control circuit. This circuit protects against overload and short circuit, PWM range can be adjusted from 0-100%, PWM frequency is 100HZ-5KHZ adjustable. Operation voltage from +8V~ 35V, minimum current consumption is about 35mA. Maximum current can go up to 6.5A. Efficiency better than 90% at full load. The functions of three trim pots are as follow: VR1: setting the minimum output voltage VR3: setting the maximum output voltage VR2: setting the output frequency.