Free Electronic Circuit Schematics » IC 4027 http://www.free-circuit.com Circuit diagram for Power supply,Battery Charger,Power amplifier,Inverter,Converter Wed, 14 Dec 2011 00:09:59 +0000 http://wordpress.org/?v=2.8 en hourly 1 Optical Switch Circuit with 2N5777 http://www.free-circuit.com/optical-switch-circuit-with-2n5777/ http://www.free-circuit.com/optical-switch-circuit-with-2n5777/#comments Fri, 20 Nov 2009 15:55:57 +0000 admin http://www.free-circuit.com/?p=356

optical switch circuit
optical switch circuit

For detail in this circuit ,i will be to present thus as below.

When the phototransistor (2N5777)is determined by the IR light, and leads to tension between the stroken 220k Ohm R resistance (any) for drive collector BC558 and the drop PHOTOTRANS from VCC to lower levels.

IC4027 TTL signal output will be drive to SL100 for drive current to relay active.

When the voltage drops lower than VCC / 3 activates the BC558, and rise (from 0 to VCC). The amount of light striking the PHOTOTRANS necessary to bring its collection of VCC / 3 through the resistor .

 (icollector Vdrop * = R, so that if necessary,

Vdrop VCC = 2 * / 3,

the resistance threshold current sentence R * is determined VCC = 2 / (icollector * 3)).

PHOTOTRANS High sensitivity would need some ‘resistance, and phototransistors weak resistance of higher value is possible even with a trimmer for the threshold precisely. The time of the phototransistor is not critical. The 4027 high-current capacity, and various devices, such as bipolars, relays, relay units + bipolars, MOSFETs, MOSFET + totem, or a logic output (see photo).

In the event that something triggers the gate when the blocks (such as an alarm system or a multi-level gauss rifle) is required to view the output you get with a small bipolar transistors wired in a configuration inversion reversed ( image) or swap the positions of the phototransistor with the resistance, so that the tension has been locked down VDC / 3 A: The formula for determining the resistance, turn left at icollector R = VCC / (icollector * 3).

]]> http://www.free-circuit.com/optical-switch-circuit-with-2n5777/feed/ 0 Low Cost Stepper Motor Circuit with IC 4027 http://www.free-circuit.com/low-cost-stepper-motor-circuit-with-ic-4027/ http://www.free-circuit.com/low-cost-stepper-motor-circuit-with-ic-4027/#comments Wed, 22 Jul 2009 03:27:21 +0000 admin http://www.free-circuit.com/?p=213 stepper motor controller circuit

stepper motor controller circuit

I had immediately into my document. I do not know where it came from, but it seems that I photocopy a few years.

I think it should be very helpful, so I decided it here. The circuit is very simple and inexpensive. It is a good thing, since most lines step motor controllers are very expensive. The circuit is made of standard components and can easily be adjusted by a computer. If you cheap surplus transistors and stepper motor, the price of the circuit can be less than $ 15.

     This stepper controller circuit shown here can used to control the unipolar stepper motor,
which has 4 coils . The stepper controller circuit can drive for a motor current of up to about 500 mAmp/Winding by suitable heat sinks for the SL-100. directsinks
      In higher currents power transistors seem 2N3055 can be used as darlington pair along with SL-100. All diodes are used to protect back current the transistor from transients.

*** Remark ***

  • You may be able to substitute any standard (2N3055) power transistor for Q1-Q4 or

    • get IC type UL to modify for transistor.

  • Every time in move the motor put signal the STEP line is pulsed, the motor moves one step.
  • Switch S1 for changes the motors direction

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