Power unit 1... 29 Volts

03/10/2018 - 16:12

In many modern stabilizers for improvement of their quality indicators the operational amplifiers possessing big factor of strengthening and stable characteristics use. However rather simple updating of the transistor stabilizer traditional on the circuit allows to improve considerably its technical characteristics and to avoid some difficulties arising at designing of stabilizers with application of OU (especially in devices with regulation of target tension largely). The high factor of stabilization of the described power unit is caused by the amplifier with dynamic loading

the Source of exemplary tension is collected on the field transistor that gives the chance to reduce target resistance of the stabilizer and to receive deep regulation of target tension.

the Main technical characteristics

Tension on an entrance of the stabilizer, Volt

30

Limits of regulation of target tension, Volt

1 … 29

Maximum current of loading, Ampere

2

Factor of stabilization of tension, dB

60

Target resistance, megohm

0,5 … 10

Temperature instability of day off tension in the range of temperature 20. . 50* From, no more, than a %

0,5

Instability of target tension of the stabilizer usually develops of instability of exemplary tension and OU drift. In the described stabilizer it is defined generally by only temperature drift of the first active element.

the Stabilizer (see the circuit) consists of two amplifiers with dynamic loading with consecutive management. The first is transistorized by V13, V12 where V13 is included according to the circuit with the general lock, and V12 — with the general collector; the second — on transistors V14, V15 (V14 — with the general emitter, and V15 — with the general collector). The feedback signal from the R9 resistor cursor, enclosed to a V13 transistor source, amplifies without inverting of a phase and arrives on base of the V14 transistor. The V13 transistor works in a mode close to an otsechka of a current. Tension between a source and a lock is exemplary in the stabilizer. The chain of R2R3V11 serves only for temperature compensation of change of a current of a drain of the V13 transistor (without it at the lock of this transistor closed on the general wire target tension of the stabilizer changes on 3... 5 % in a temperature interval 20... 50 °C).

From a V14 transistor collector the pro-inverted and strengthened signal is transferred to font by p to base of the powerful regulating V15 transistor.

the Operating element eats font from the parametrical stabilizer on a stabilitron of V10 and the V9 transistor. For receiving higher efficiency of tension of the main rectifier (see article “Improvement of low-power voltage stabilizers” — "Radio", 1981, No. 10, page 56) V1 — V4 the stabilizer on the V9 transistor eats from the tension multiplier on V5 diodes — V8 and condensers C1, С2. The multiplier is connected to a secondary winding of the T1 transformer. Lamp Н1 serves for restriction of a collector current via transistors V9, V14 and a base current of the V15 transistor at short circuit in a loading chain, and also for overload indication. At the moment of an overload owing to increase of a base current of the V15 transistor there is a voltage reduction on an entrance of the parametrical stabilizer to level 30 In where this tension almost completely falls on lamp Н1 minus power failure on transistors V9, V14 and emitterny transition of the V15 transistor. The current on this chain does not exceed 120... 130 мА that less maximum permissible for its elements.

In the stabilizer is used by font the wire variable resistor with admissible capacity of dispersion of 3 W (PPB-3, PP3-40). The V13 transistor is necessary for picking up with small value of an initial current of a drain — only then the bottom limit of target tension of the stabilizer will be close to 1 V.Tok of a drain of this transistor at tension between a drain and a source 10 In and a lock closed on a source, should be within 0,5... 0,7 мА. At stabilizer installation between the V11 diode and the V13 transistor it is necessary to provide good thermal contact for what it is enough to stick together their cases. It is desirable to choose the V15 transistor with big static factor of transfer of a current of base. Except specified on the circuit, it is possible to use silicon transistors of the series KT203, КТ208, КТ209, КТ501, КТ502, КТ3107 (V12), КТ814, КТ816 (V14), transistors KT815, КТ817 with any alphabetic index, КТ807Б (V9), КТ803А, КТ808А, КТ819 with any alphabetic index (V15).

In the stabilizer can apply and germanic MP40A transistors, and also any of the series MP20, МП21, МП25, МП26 (V12), ГТ402, ГТ403, П213 — П215 (V14). Instead of КС527А it is possible to apply stabilitrons Д813, Д814Д (on two it is consecutive), Д810, Д814В (on three is consecutive). It is desirable to establish V9 and V14 transistors on small radiators (with a useful area 20. . 30 cm 2 ). to

is necessary For the V15 transistor a radiator with a useful area not less than 1500 cm 2 . For the purpose of simplification of a thermal mode of this transistor step change of tension on a stabilizer entrance is provided by the S1 toggle-switch calculated on a current 2 And. In situation 1 on an entrance of the stabilizer moves 15 In, and in 2 — 30 V.Kogda's position the toggle-switch is in situation 2 and resistance of loading closely to a minimum, the stabilized tension it is not necessary to establish less than 15 Century

to

the Network transformer is reeled up on магнитопроводе transformatorats-60. Primary winding is left without change, secondary is rewound; it contains 200 rounds (on 100 rounds on each coil) wires PEV-2 1,16.

For increase of reliability of the stabilizer it can add with the protection device described in article “The protection device for transistors” ("Radio", 1980, No. 9, page 63). High-frequency generation arising sometimes in the stabilizer can be suppressed or increase in face value of the C6 condenser, or inclusion in a chain of base of the V15 transistor of the resistor resistance 5... 10 Ohm in capacity of 1 W. For ensuring steady operation of the stabilizer its installation needs to be carried out the conductors of the minimum length having big section of a current-carrying vein.

A.GRIGORIEV
Radio 3/84g. />

!>
Power unit 1... 29 Volts

Similar entries

  • Six-element frame aerial
  • The aerial a threefold square from one piece of a wire
  • Fluorescent lamp start without a starter
  • Broadband amplifier
  • Voltage stabilizer on OU