The MC34164 VS used in the Chloroplast SE is different in one respect from the 1381 VS (used in the VTSE and 1381 SEs) in that the MC34164 has an `open drain` output which requires a pull up resistor to the positive supply for the output to go positive. The CSE uses a resistor in series with the 34164 chip input and takes advantage of the fact tha
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t the quiescent supply current for the 34164 is higher when the output is low and decreases to almost zero when the output is high. That means the voltage drop across that series input resistor, generated by the quiescent 34164 current, must be added to the rated "turn on" voltage which raises the voltage on the supply cap required to turn on the 34164 (ie to 7V). After the 34164 turns on, the quiscent 34164 current drops to zero and the voltage drop across the series resistor also drops to zero, so that the voltage at the 34164 input pin suddenly jumps up to the supply cap voltage. The voltage at the "open" 34164 output pin is now pulled up to the supply through the output resistor, but the output pin voltage only rises to the forward voltage of the darlington transistor base emitter junction or about 1. 2V. The darlington turns on and the collector supplies current to the rest of the circuit. The supply cap voltage starts to drop as the motor load etc depletes the cap charge until the supply voltage reaches the 34164 rated turn off voltage (ie 5V) and the process repeats In one of my earlier MC34164 hysteresis SE designs (hySE), the 34164 upper threshold was raised by inserting a resistor in the ground lead and using the voltage drop generated from quiesent current and sinking the current from the output pull up resistor. Craig Maynard greatly improved on that design using the same principle but simplifying the circuit in...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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