Current and time based switch 
 Temperature limiter 
 Thermostat 

J

J

Household appliances

J

J

Electronics

J

J

Fan heaters

J

J

Automotive industry

Applications

J

J

Highest safety by self hold types

J

J

PCB terminals available

J

J

Customized ratings

J

J

Manual reset

Benefits

A

10

20

30

40

type ratings

control

A10V
A11V

A20V
A21V

A30V
A31V

A40V
A41V

function

automatic

manual

self hold

230 V

self hold

120 V

version

normally closed

VDE

rated current at 50 / 60 Hz ( power factor 0.95 / 0.6 )

16 A / 2.5 A (250 V)

16 A / 2.5 A (250 V)

16 A / 2.5 A (230 V) 19.2 A / 2.5 A (120 V)

switching cycles

10,000

1,000

10,000

8,000

temperature range T

A

  ( steps in 5 °C )

70 °C ... 160 °C

70 °C ... 130°C / 140 °C

70 °C ... 160 °C

UL

rated current at 50 / 60 Hz ( power factor 1.0 / 0.75 ) 

16 A / 6.3 A (250 V)

16 A / - (125 V)

switching cycles

6,000

temperature range T

A

  ( steps in 5 °C )

70 °C ... 160 °C

max. current at 250 V 50/60Hz ( power factor 0.95 ) 

25 A

switching cycles under max. current

200

tolerance

standard: ± 5 °C

feature of automatic action

1.B, 2.B

2.B

2.C.AK

contact resistance

< 50 m

Ω

hysteresis / reset temperature 

1)

30 °C ± 15 °C / - 

 - / < -20 °C ; < -10°C 

- / < -20 °C 

2)

suitable for use in protection class

I, II

approvals

VDE / ENEC

EN 60730-1 / -2-9

UL

UL 873

CSA

C22.2 No. 24 

3)

CQC

GB14536.1-1998 / GB14536.10-1996 

4)

1)

 at the T

A

 (upper and lower) limits the hysteresis could deviate    

2)

 without air flow     

3)

 different power rating     

4)

 details on request

For special applications version P is available with a very low self heating rate. 
Manual reset: The maximum operating force must not exceed 6 N. The control should not be reset before  
the starting conditionsare reached, meaning there should be a satisfactory cooling down time! 
Technical data on request.

  Technical data    

Series A switches are based on a complex system consisting of a contact spring 
unit and a thermo-bimetal snap-disc. When heating up to the fixed switching 
point, the contact opens and thus interrupts the power circuit.
They  are  very  flexible  to  use:  Due  to  the  different  types  of  reset  and  the 
adjustable current sensitivity for quick shutdowns, the A switches offer high 
quality solutions, especially in very specific safety concepts. 
Temperature switch with automatic reset A10: After a certain cooling phase 
(temp. hysteresis) the contact switches back automatically. 
Temperature limiter with manual reset A20: After opening the contacts and the 
subsequent cooling the contacts remain open until a manual reset is performed 
on the reset pin.
Temperature switch with electr. self-hold A30 (230V) / A40 (120V): After 
opening the contacts the switch is heated by a parallel connected resistor 
and thus kept open. The automatic reset is only performed through a mains 
disconnection, or off-switching of the device in which the temperature switch 
is installed.

  Description    

code

used in TCO

illustration

drawing dimensions ( mm )

technical  

specification

approvals

standard 

A10, A11, A12, A13 
A20, A21, A22, A23 
A30, A31, A32, A33 
A40, A41, A42, A43 

7,

2

33,5

4,

8

2,

6

O 2,6

26,6

3,5

0,

5

terminals for 

soldering, screwing, 

riveting or welding-

CuNi18Zn20 

1)

VDE, UL, CSA

A321

A10, A12
A20, A22
A30, A32
A40, A42

0,

5

4,

5

20,3

26,8

4,

8

2,

5

3,7

SMD terminals
CuNi18Zn20 

1)

VDE, UL

A322

A10, A12
A20, A22
A30, A32
A40, A42

2,

7

4,

8

26,5

4,7

0,5

3,

4

3,

3

THT terminals

CuNi18Zn20 1) 

Anschlüsse

CuNi18Zn20 

1)

VDE, UL

1)

 P types have terminals of CuFe2P material

TCO

illustration

drawing dimensions ( mm )

technical 

specification

approvals

standard

current - time 

based 

1)

A10V

A12V

7,

2

33,5

4,

8

0,

5

5,

4

base of thermoset-

ting plastic

VDE, UL, CSA

A11V
A21V
A31V
A41V

A13V
A23V
A33V
A43V

33,5

11

4,

8

17

7,

2

8,

1

5,

4

0,

5

3,

2
O

screw-on fixing base 

of thermosetting 

plastic

VDE, UL, CSA

A20V

A22V

7,

2

0,

5

4,

8

33,5

1,5

O

2,

5

5,

6

manual reset base 

of thermosetting 

plastic 

possible srew-on 

fixing dimensions 

see above

VDE, UL, CSA

A30V
A40V

A32V
A42V

0,

5

0,

7

ca

.

7,

2

33,5

5,

4

4,

8

voltage maintained 

PTC 120V or 230V 

base of thermoset-

ting plastic

possible screw-on 

fixing dimensions 

see above

VDE, UL, CSA

1)

 For current-time based types (execution D, J, K, L, M, P, R, V) the following information must be provided:

J

J

GDC or AC voltage U

N

 in Volts.

J

J

Continuous operating current I

C

 in Amps at which the switch must not respond.

J

J

Current level I

0

 in Amps at which the switch must respond and the response time t

0

 (in seconds ± tolerance).

J

J

Ambient temperatures which could be experienced both in normal operation and in switching conditions.

J

J

Maximum current in Amps.

  Versions    

Täschenwaldstr. 3 
75181 Pforzheim 
Deutschland 

Tel.: +49 7231 787-0 
Fax: +49 7231 787-155 

 
info@microtherm.de 
www.microtherm.de

Microtherm GmbH

05/2017-Technical subject to change without notice

A 10P

A 10V

current I

0

 [A]

self-heating [°

C ]

0

0

5

5

10

10

15

15

20

30

25

0

0

5

5

10

10

15

15

20

30

25

D, J, K, L,

M, P, R, V

current I

0 

[A]

response time t

0

 [°

C ]

Test conditions: 
Measurement in air flow and lead wires of 1.5 mm

2

.

TCO variations for current-time based applications. 

  Ordering example    

  Current vs. self heating    

  Marking    

  Current vs. response time    

type

execution

temperature

tolerance

terminal code

A 10 V 120 05 A321

A10V

type and execution

D     

country (D=Germany)

12005

response temperature (120°C), tolerance (± 5°C)

057

date of manufacture (May 2017) 

A12D

type and execution

H

country (H=China)

--123

customized type with drawing number

057

date of manufacture (May 2017)