ECONOMICAL PN-70 | MODEL CONSTRUCTION

As a stand-alone power source flash FIL-46 I use a voltage Converter PN-70, manufactured by Kharkiv enterprises “ECHO”. In the process of operation of this device revealed its drawback: after charging the storage capacitor and ignition indicator lights, signaling willingness to work consumed by the inverter current decreases from 1.5 A to About 1 A, that is, the batteries are not disabled and continue to discharge. This leads to rapid failure. To stop the discharge of the batteries is possible by disabling the flash from the unit manually by taking out the plug from the socket or set forth in the chain of socket switch. However, both methods are inconvenient due to the fact that distract from the shooting.

To eliminate these shortcomings, I have designed and manufactured control unit, which is in the “pause” reduces the Converter current from 1 A to 0.1 A, that is, 10 times. During the design of the machine used recommendations from the book by G. Fedotov, “Electrical and electronic devices for photos” (Leningrad, Energoatomizdat, 1984).

Schematic diagram of the modified power supply is shown in the figure. Highlighted part of the circuit, subjected to alteration. The automatic controller. As the charging of the storage capacitor of the flash increases voltage divider RS—R6. Once the capacitor charged to the desired voltage (300 to 280…), opens the diode VD2, and also increases the current on the resistor R4; this leads to the locking of the transistors VT4 and VT3 and an increase in the resistance of transistor VT2. The consumed battery current is reduced, and in addition, stabiliziruemost power flash.

Fig. 1. Concept modernizirovana power supply PN-70:

GB1 — battery type 3336 (2), TV1 — transformer R1 — 360 Ohm R2 — 36 Ohm S1 — 50 мкФХ12, C2 — 0,025 µf, VT1— КТ837К, VDI — КД105Б, VT2 — КТ837К, VT3 — ГТ403Б, VT4 —МП42Б, VD2 — Д814В, R3 — 47 Ohms, R4 is 150 ohms, R5 is 2.4 Mω, R6 — 360 com.

R and p. 2. Printed circuit Board device with the arrangement of the elements of a — hole 0 3 mm to replay Board in the transmitter housing

R and S. 2. Printed circuit Board device with the arrangement of the elements of a — hole 0 3 mm to replay Board in the enclosure.

R and p. 3. The appearance of the upgraded power supply

R and S. 3. The appearance of the upgraded power supply.

The device is mounted on the circuit Board. Its dimensions are adapted to the accommodation directly in the transmitter housing without any additional modifications. Mount circuit Board parts are connected to the Converter Board with the screw MOH and three nuts. In this case, carefully bend the tweezers the terminals of the capacitor C1 and resistor R1 to reduce their height. The change of the Converter circuit is to break the jumper from the “plus” of the power source to the emitter of the transistor VT1 and the inclusion instead of “plus” of the VT2 emitter and the VT1 emitter — collector VT2.

Transistor VT2 is supplied with a heat sink made of copper strips 0.5 mm thick, with dimensions 22X50 mm. For ease of placement in the housing of the heat sink is bent.

Setting unit is to set the required voltage to open diode VD2 via the resistors R5—R6 (while maintaining the inverter output voltage 280…300 V).

O. PANIC, And R p e n s. Kiev region.

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