General view

CT 10.21

IPRS Băneasa

Year
Unknown
Category
Components
Type
Capacitors
Documentation score
1/5
Last edited
16 OCT 2026

Specifications

Type
ceramic trimmer
Capacitance (Cn)
5…100 pF
Capacitance, min
5 pF
Capacitance, max
100 pF
Minimum capacitance, at most
5.5–22 pF (see Variants)
Maximum capacitance, at least
18–90 pF (see Variants)
Rated voltage (Un)
350 V
Dissipation factor (tan δ)
≤ 20·10⁻⁴ (1 MHz)
Dielectric strength
1025 V (1st edition: 1025 V DC)
Temperature coefficient (αC)
(−200…−900)·10⁻⁶/°C, (−800…−1800)·10⁻⁶/°C (see Variants)
Climatic category
25/085/04
Marking
violet, blue (see Variants)
Package
disc trimmer, type II
Rotation torque
200…1200 gf·cm
Application
radio-frequency circuits

Sources: [1][2]

Variants (6)

CT 10.21 (5…20 pF, −200…−900)5…20 pF5205.518(−200…−900)·10⁻⁶/°Cviolet
CT 10.21 (6…25 pF, −200…−900)6…25 pF6256.622.5(−200…−900)·10⁻⁶/°Cviolet
CT 10.21 (7…30 pF, −200…−900)7…30 pF7307.727(−200…−900)·10⁻⁶/°Cviolet
CT 10.21 (10…40 pF, −200…−900)10…40 pF10401136(−200…−900)·10⁻⁶/°Cviolet
CT 10.21 (20…100 pF, −200…−900)20…100 pF201002290(−200…−900)·10⁻⁶/°Cviolet
CT 10.21 (20…100 pF, −800…−1800)20…100 pF201002290(−800…−1800)·10⁻⁶/°Cblue

Click a column heading to sort. „+” adds a variant to the comparison (CT 10.21).

Description

The CT 10.21 is a series of type II ceramic disc trimmer capacitors, rated 350 V DC, for radio-frequency circuits [1]. The Agenda radioelectronistului (2nd edition, 1989) lists six versions, from 5…20 pF to 20…100 pF, each with the largest value of its minimum capacitance, the smallest value of its maximum capacitance, its temperature coefficient and its colour marking; it names no standard and does not explain „type II” [1].

The Agenda does not say which works made the series: for the whole section on capacitors made in Romania it lists IPEE Electroargeș of Curtea de Argeș, Tehnoton of Iași, IIS Electronica of Bucharest and IPRS Băneasa as producers, and the 1st edition (1983) names only the first three [3][4]. It is listed here as made by IPRS Băneasa; Un secol de electronică în România says that the ceramic capacitor line of IPRS passed to IPEE Curtea de Argeș in 1973 [5].

Coded as [3]:

Part Meaning
CT construction type: adjustable ceramic capacitor, disc type („trimere”)
10 (in the book’s example CT 10.11) technological family („familia tehnologică”)
11 (in the book’s example CT 10.11) package code („codul capsulei”)

A dot of paint on the body gives the range of the temperature coefficient: orange +100…−200, violet −200…−900, blue −800…−1800 (×10⁻⁶/°C) [3].

The 1st edition (1983) has no marking column and other versions: 5…20 pF (with a maximum of at least 10.8 pF), 7…25, 8…30 and 15…47 pF instead of 6…25, 7…30 and 10…40 pF [2][1].

Rated voltages are DC („Vcc”). Dimensions in mm (fig. 20.66): 21.3 ± 1 × 16 ± 1, height ≤ 10, 44 across the two mounting tabs (1st edition: ≤ 44), hole Ø 2.3 [1][2].

Gallery

IPRS Băneasa CT 10.21: Drawing (fig. 20.66)No image available
Drawing (fig. 20.66)

Documents

No documents available yet.

References

  1. [1]N. Drăgulănescu – „Agenda radioelectronistului”, 2nd edition, Editura Tehnică, 1989, section 20.4.5.5 „Condensatoare ceramice ajustabile, disc, tip II, seria CT 10.21”, p. 304
  2. [2]N. Drăgulănescu – „Agenda radioelectronistului”, 1st edition, Editura Tehnică, 1983, section 3.5.4.5.5 „Condensatoare ceramice ajustabile disc, tip II, seria CT 10.21”, p. 273
  3. [3]N. Drăgulănescu – „Agenda radioelectronistului”, 2nd edition, Editura Tehnică, 1989, sections 20.4 „Condensatoare produse în R.S.R.” (p. 248) and 20.4.5.1 „Codificare – marcare (în clar)” (p. 301)
  4. [4]N. Drăgulănescu – „Agenda radioelectronistului”, 1st edition, Editura Tehnică, 1983, sections 3.5.4 „Condensatoare produse în R.S.R.” (p. 218) and 3.5.4.5.1 „Codificare – marcare (în clar)” (p. 270)
  5. [5]N. Millea, I. Constantinescu (coord.) – „Un secol de electronică în România”, Editura Academiei Române, 2020, section VIII.1.2.6, pp. 408–411