Rongge

IC Timer 555 has a basic PWM controller with pulse width control feature 0 .. 100% which is controlled using the R1, at the time of controlling the oscillator frequency relatively stabi so it may be used to build the Simple PWM controller. Frequency of Simple PWM controller 555 depending on the value of R1 and C1, values ​​shown R1 and C1 will form the output with a frequency of 170 to 200 Hz. Diode-diode used in the Simple PWM controller With this 555 can use a 1N4148. R2, R3 and C3 form a giver triger circuit beginning at the reset IC 555 for 2 seconds. If you want to use a series of Simple PWM controller 555 with the V + not +12 V, it does not matter to raise tilapia R2 where (V + * R2) / (R2 + R3) is about 2, because it limits the signal level reset is 0.5 .. 1V. If you do not do that, then signal the kickstart to get too close to the limit reset signal reception. PWM controller circuit Q output of 555 on the Simple PWM controller circuit 555 is used for driver PWM pulse, so that t...

Description. Here is the circuit diagram of a simple stepper motor controller using only elementary parts. The driver circuit uses, four transistor (SL100) to drive the motor windings, two NOT gates and one XOR gate to decode the two bit control logic to drive the four windings of the motor. The diodes D1 to D4 protects the corresponding transistors from transients generated during the switching of motor windings. d0 and d1 are the control logics which determines the direction of rotation as well as speed. Circuit diagram with Parts list. Notes. The control logic for the circuit can be obtained from a 2 bit up/down counter clocked by a 555 astable multivibrator.The direction of count determines the direction of rotation and the frequency of astable multivibrator determines the speed of rotation. As shown in the schematic above, IC1a IC1b belongs to same IC 7404. Pin 14 and pin 7 of both IC1 and IC2 must be connected to +5 V and ground respectively, though it is not shown in circui...

This circuit operates an automotive windscreen washer pump to fill a 20-litre drum from a 205-litre water reservoir. The drum is suspended above a drip line, which irrigates a vegetable garden. Two stainless steel probes mounted in the drum act as sensors for the system. One probe is positioned at the high water mark, the other at about half-full. The pump power is switched by a 12V automotive relay (RLY1). Two op amps (IC1a & IC1b) connected as voltage comparators form the basis of the circuit.  Initially, assume a falling water level with the pump switched off. When the water level exposes the lower probe, the non-inverting input (pin 5) of IC1b rises to about 7.4V. With trimpot VR2 correctly adjusted, this will be higher than the voltage on pin 6. The output (pin 7) therefore swings high, biasing Q1 into conduction. This in turn causes Q4 to conduct, switching on the relay and starting the pump.  In addition, when Q4 switches on it supplies base current to Q3 via a 6.8k...